tag:blogger.com,1999:blog-230212552012-06-01T03:09:59.108+02:00Internetworking perspectives by Ivan PepelnjakIvan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.comBlogger1596125CiscoIosHintsAndTrickshttp://feedburner.google.comSubscribe with My Yahoo!Subscribe with My AOLSubscribe with BloglinesSubscribe with GoogleSubscribe with PageflakesSubscribe with Live.comAdd to Any Feed Readertag:blogger.com,1999:blog-23021255.post-84441321664825394622012-05-31T07:56:00.000+02:002012-05-31T07:56:00.881+02:00<p>Understanding equal-cost multipathing in <a href="http://blog.ioshints.info/2012/05/brocade-vcs-fabric.html">Brocade’s VCS Fabric</a> is a bit tricky, not because it would be a complex topic, but because it’s a bit counter-intuitive (while still being perfectly logical once you understand it). Michael Schipp <a href="http://packetpushers.net/understanding-brocades-isls-and-ecmp-just-a-wee-bit-more/">tried to explain how it works</a>, Joel Knight <a href="http://www.packetmischief.ca/2012/05/23/five-features-of-brocade-vcs/">went even deeper</a>, and I’ll try to draw a parallel with the routed networks because most of us understand them better than the brave new fabric worlds.</p><a href="http://blog.ioshints.info/2012/05/equal-cost-multipath-in-brocades-vcs.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-8444132166482539462?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=SbkEP_wBN-c:CzsLbmPsX-8:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=SbkEP_wBN-c:CzsLbmPsX-8:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=SbkEP_wBN-c:CzsLbmPsX-8:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=SbkEP_wBN-c:CzsLbmPsX-8:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=SbkEP_wBN-c:CzsLbmPsX-8:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=SbkEP_wBN-c:CzsLbmPsX-8:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=SbkEP_wBN-c:CzsLbmPsX-8:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=SbkEP_wBN-c:CzsLbmPsX-8:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=SbkEP_wBN-c:CzsLbmPsX-8:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/SbkEP_wBN-c" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com4http://blog.ioshints.info/2012/05/equal-cost-multipath-in-brocades-vcs.htmltag:blogger.com,1999:blog-23021255.post-91135076181509429462012-05-30T07:03:00.000+02:002012-05-30T07:03:00.278+02:00<p>A while ago I was writing about the behavior of <a href="http://blog.ioshints.info/2012/02/microsoft-network-load-balancing-behind.html">Microsoft’s Network Load Balancing</a>, the problems it’s causing and how Microsoft tried to hack around them using multicast source MAC addresses in ARP replies (which is illegal). A few days ago one of my readers asked me whether I know which RFC prohibits the multicast MAC address in ARP replies.</p><p>A quick consultation with friendly Google search engine returned <a href="http://fixunix.com/tcp-ip/66685-arp-reply-containing-multicast-mac-ok.html">this web page</a>, which contained the answer: <a href="http://tools.ietf.org/html/rfc1812#section-3.3.2">section 3.3.2 of RFC 1812</a> (Requirements for IP Version 4 Routers):</p><blockquote class="cite">A router MUST not believe any ARP reply that claims that the Link Layer address of another host or router is a broadcast or multicast address.</blockquote><p>Problem solved – now I know the real reason we have to configure <a href="http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_example09186a0080a07203.shtml#mm">static ARP entries on Cisco routers and switches</a>.</p><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-9113507618150942946?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=cAre7T42pIs:6vgM38oZ9_Y:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=cAre7T42pIs:6vgM38oZ9_Y:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=cAre7T42pIs:6vgM38oZ9_Y:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=cAre7T42pIs:6vgM38oZ9_Y:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=cAre7T42pIs:6vgM38oZ9_Y:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=cAre7T42pIs:6vgM38oZ9_Y:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=cAre7T42pIs:6vgM38oZ9_Y:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=cAre7T42pIs:6vgM38oZ9_Y:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=cAre7T42pIs:6vgM38oZ9_Y:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/cAre7T42pIs" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com5http://blog.ioshints.info/2012/05/arp-reply-with-multicast-source-mac-is.htmltag:blogger.com,1999:blog-23021255.post-16165328598030806482012-05-28T07:08:00.000+02:002012-05-28T07:08:00.306+02:00<p>This topic has been on my to-write list for over a year and its working title was phrased as a question, but all the horror stories you’ve shared with me over the last year or so (some of them published in my blog) have persuaded me that there’s no question – it’s a fact.</p><p class="note">If you think I’m rephrasing the same topic ad nauseam, you’re right, but every month or so I get an external trigger that pushes me back to the same discussion, this time <a href="http://it20.info/2012/05/typical-vxlan-use-case/">an interesting comment thread on Massimo Re Ferre’s blog</a>.</p><a href="http://blog.ioshints.info/2012/05/layer-2-network-is-single-failure.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-1616532859803080648?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=NNx5ij7drGg:ZkeBAz3fC60:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=NNx5ij7drGg:ZkeBAz3fC60:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=NNx5ij7drGg:ZkeBAz3fC60:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=NNx5ij7drGg:ZkeBAz3fC60:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=NNx5ij7drGg:ZkeBAz3fC60:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=NNx5ij7drGg:ZkeBAz3fC60:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=NNx5ij7drGg:ZkeBAz3fC60:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=NNx5ij7drGg:ZkeBAz3fC60:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=NNx5ij7drGg:ZkeBAz3fC60:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/NNx5ij7drGg" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com18http://blog.ioshints.info/2012/05/layer-2-network-is-single-failure.htmltag:blogger.com,1999:blog-23021255.post-37609357211146998382012-05-25T07:22:00.000+02:002012-05-25T07:22:31.335+02:00<div class='separator'><a href="http://dilbert.com/strips/comic/2012-05-25/"><img src="http://dilbert.com/dyn/str_strip/000000000/00000000/0000000/100000/60000/0000/400/160498/160498.strip.gif" width="520"></a></div><p>No comment necessary.</p><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-3760935721114699838?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=sIpUWmjpt7g:qOfcM0PNXZY:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=sIpUWmjpt7g:qOfcM0PNXZY:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=sIpUWmjpt7g:qOfcM0PNXZY:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=sIpUWmjpt7g:qOfcM0PNXZY:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=sIpUWmjpt7g:qOfcM0PNXZY:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=sIpUWmjpt7g:qOfcM0PNXZY:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=sIpUWmjpt7g:qOfcM0PNXZY:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=sIpUWmjpt7g:qOfcM0PNXZY:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=sIpUWmjpt7g:qOfcM0PNXZY:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/sIpUWmjpt7g" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com3http://blog.ioshints.info/2012/05/move-it-to-cloud.htmltag:blogger.com,1999:blog-23021255.post-60037133140954590482012-05-24T07:17:00.000+02:002012-05-24T16:18:32.679+02:00<p>We knew Brocade has OpenFlow support in its devices <a href="http://blogs.wsj.com/digits/2011/05/03/arista-brocade-open-to-networking-apps/">for at least a year</a>; now it’s official: OpenFlow is supported on its MLX-series routers. But wait, there’s more: that’s just the first step in Brocade’s long-term SDN strategy, <a href="http://newsroom.brocade.com/easyir/customrel.do?easyirid=74A6E71C169DEDA9&amp;version=live&amp;prid=890051&amp;releasejsp=custom_184">according to their press release</a>. Let’s take a deeper look at that strategy.</p><a href="http://blog.ioshints.info/2012/05/brocade-yet-another-sdn-strategy.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-6003713314095459048?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Jzk0IZGHJ9w:VtqOSPYnRAI:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Jzk0IZGHJ9w:VtqOSPYnRAI:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Jzk0IZGHJ9w:VtqOSPYnRAI:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Jzk0IZGHJ9w:VtqOSPYnRAI:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Jzk0IZGHJ9w:VtqOSPYnRAI:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Jzk0IZGHJ9w:VtqOSPYnRAI:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Jzk0IZGHJ9w:VtqOSPYnRAI:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Jzk0IZGHJ9w:VtqOSPYnRAI:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Jzk0IZGHJ9w:VtqOSPYnRAI:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/Jzk0IZGHJ9w" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com2http://blog.ioshints.info/2012/05/brocade-yet-another-sdn-strategy.htmltag:blogger.com,1999:blog-23021255.post-59881598673815640282012-05-23T07:02:00.000+02:002012-05-23T07:02:00.022+02:00<p>A while ago I wrote about <a href="http://blog.ioshints.info/2011/05/stateless-nat64-is-useless.html">uselessness of stateless NAT64</a> and got in nice discussion with <a href="https://twitter.com/toreanderson">Tore Anderson</a> who wanted to use stateless NAT64 in reverse direction (stateless NAT46) to build an IPv6-only data center. Some background information first (to define the context of his thinking before we jump into the technical details):</p><a href="http://blog.ioshints.info/2012/05/ipv6-only-data-center-built-by-tore.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-5988159867381564028?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=xTe7euAdAA8:ZNgEfpbfUuA:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=xTe7euAdAA8:ZNgEfpbfUuA:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=xTe7euAdAA8:ZNgEfpbfUuA:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=xTe7euAdAA8:ZNgEfpbfUuA:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=xTe7euAdAA8:ZNgEfpbfUuA:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=xTe7euAdAA8:ZNgEfpbfUuA:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=xTe7euAdAA8:ZNgEfpbfUuA:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=xTe7euAdAA8:ZNgEfpbfUuA:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=xTe7euAdAA8:ZNgEfpbfUuA:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/xTe7euAdAA8" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com5http://blog.ioshints.info/2012/05/ipv6-only-data-center-built-by-tore.htmltag:blogger.com,1999:blog-23021255.post-5976984209727562702012-05-22T12:49:00.000+02:002012-05-22T12:49:00.509+02:00<p>Some of you have noticed that I’d changed the commenting system on my blog recently. Here’s the full story (with a question for you at the very end).</p><p>I was totally fed up with Blogger comments years ago and decided to look for an alternative. JS-Kit was a perfect solution and it even allowed me to import Blogger comments and synchronize new entries with Blogger (so I could turn it off at any time and retain my comments).</p><a href="http://blog.ioshints.info/2012/05/goodbye-echo-ill-miss-you.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-597698420972756270?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=DBFvvhIehu8:BeCYFlLa9AM:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=DBFvvhIehu8:BeCYFlLa9AM:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=DBFvvhIehu8:BeCYFlLa9AM:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=DBFvvhIehu8:BeCYFlLa9AM:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=DBFvvhIehu8:BeCYFlLa9AM:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=DBFvvhIehu8:BeCYFlLa9AM:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=DBFvvhIehu8:BeCYFlLa9AM:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=DBFvvhIehu8:BeCYFlLa9AM:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=DBFvvhIehu8:BeCYFlLa9AM:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/DBFvvhIehu8" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com10http://blog.ioshints.info/2012/05/goodbye-echo-ill-miss-you.htmltag:blogger.com,1999:blog-23021255.post-7669318209294352062012-05-21T07:48:00.000+02:002012-05-21T07:48:00.040+02:00<p>Stumbled across this marvel while updating my IPv6 presentations for a <a href="http://www.reissromoli.it/index.php/ipv6-e-tempo-di-migrare-ii-edizione.html">2-day seminar in Milano and Rome</a> (straight from <a href="http://www.cisco.com/en/US/docs/ios/ipv6/command/reference/ipv6_04.html#wp2519507">15.2M&amp;T command reference</a>):</p><blockquote class="cite">With IPv6 support added in Cisco IOS Release 12.2(2)T, the <strong>ip http server</strong> command simultaneously enables and disables both IP and IPv6 access to the HTTP server. However, an access list configured with the <strong>ip http access-class</strong> command will only be applied to IPv4 traffic. IPv6 traffic filtering is not supported.</blockquote><p>Wait ... WHAT? I cannot control who can access the HTTP(S) server running in Cisco IOS over IPv6 (apart from kludges like ingress ACLs on all interfaces or CoPP), and this stupidity has been left unfixed for nine(9) years?. Are we really in 2012, less than a month away from <a href="http://www.worldipv6launch.org/">World IPv6 Launch</a> or have I been transported to 1990’s?</p><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-766931820929435206?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=GArwd_CqL1M:n_Mco9JIqKc:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=GArwd_CqL1M:n_Mco9JIqKc:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=GArwd_CqL1M:n_Mco9JIqKc:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=GArwd_CqL1M:n_Mco9JIqKc:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=GArwd_CqL1M:n_Mco9JIqKc:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=GArwd_CqL1M:n_Mco9JIqKc:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=GArwd_CqL1M:n_Mco9JIqKc:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=GArwd_CqL1M:n_Mco9JIqKc:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=GArwd_CqL1M:n_Mco9JIqKc:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/GArwd_CqL1M" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com11http://blog.ioshints.info/2012/05/http-over-ipv6-on-cisco-ios.htmltag:blogger.com,1999:blog-23021255.post-91250337344778383492012-05-18T07:33:00.000+02:002012-05-18T21:21:03.594+02:00<p>Google unveiled some details of its new internal network at Open Networking Summit in April and predictably the industry press and OpenFlow pundits exploded with the “this is the end of the networking as we know it” glee. Unfortunately I haven’t seen a single serious technical analysis of what it is they’re actually doing and how different their new network is from what we have today. </p><a href="http://blog.ioshints.info/2012/05/openflow-google-brilliant-but-not.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-9125033734477838349?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8Q_yd3Vv25s:hIx2VkhRijc:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8Q_yd3Vv25s:hIx2VkhRijc:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8Q_yd3Vv25s:hIx2VkhRijc:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8Q_yd3Vv25s:hIx2VkhRijc:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=8Q_yd3Vv25s:hIx2VkhRijc:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8Q_yd3Vv25s:hIx2VkhRijc:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=8Q_yd3Vv25s:hIx2VkhRijc:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8Q_yd3Vv25s:hIx2VkhRijc:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=8Q_yd3Vv25s:hIx2VkhRijc:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/8Q_yd3Vv25s" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com17http://blog.ioshints.info/2012/05/openflow-google-brilliant-but-not.htmltag:blogger.com,1999:blog-23021255.post-87202205551509341282012-05-16T07:28:00.000+02:002012-05-16T07:28:00.475+02:00<p>Brad Hedlund did an excellent analysis of fixed versus chassis-based switches in his Interop presentation and concluded that <a href="http://bradhedlund.com/2012/05/10/comparing-efficiencies-of-fixed-vs-chassis-switches/">fixed switches offer higher port density and lower per-port power consumption than chassis-based ones</a>. That’s true when comparing individual products, but let’s ask a different question: how much does it take to implement a 384-port non-blocking fabric (equivalent to Arista’s 7508 switch) with fixed switches?</p><a href="http://blog.ioshints.info/2012/05/are-fixed-switches-more-efficient-than.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-8720220555150934128?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=jQUHH5IbMZo:NCWg4tZb2p8:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=jQUHH5IbMZo:NCWg4tZb2p8:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=jQUHH5IbMZo:NCWg4tZb2p8:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=jQUHH5IbMZo:NCWg4tZb2p8:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=jQUHH5IbMZo:NCWg4tZb2p8:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=jQUHH5IbMZo:NCWg4tZb2p8:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=jQUHH5IbMZo:NCWg4tZb2p8:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=jQUHH5IbMZo:NCWg4tZb2p8:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=jQUHH5IbMZo:NCWg4tZb2p8:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/jQUHH5IbMZo" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com5http://blog.ioshints.info/2012/05/are-fixed-switches-more-efficient-than.htmltag:blogger.com,1999:blog-23021255.post-44846752561324895632012-05-14T06:38:00.000+02:002012-05-14T07:01:32.398+02:00<p>I usually use the “<em>Nicira is Skype of virtual networking</em>” analogy when describing the differences between Nicira’s NVP and traditional VLAN-based implementations. <a href="http://www.wired.com/wiredenterprise/author/cade_metz/">Cade Metz</a> liked it so much he used it in his <a href="http://www.wired.com/wiredenterprise/2012/05/what-is-a-virtual-network/"><em>What Is a Virtual Network? It’s Not</em><em> </em><em>What You Think It Is</em></a> article, so I guess a blog post is long overdue. </p><p>Before going into more details, you might want to browse through my <a href="http://demo.ipspace.net/get/Cloud%20Networking%20Scalability%20RIPE64.pdf">Cloud Networking Scalability</a> presentation (or <a href="https://ripe64.ripe.net/archives/video/29/">watch its recording</a>) – the crucial slide is this one:</p><a href="http://blog.ioshints.info/2012/05/virtual-networks-skype-analogy.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-4484675256132489563?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=spv__uzEl1E:qvL3-vMn3lw:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=spv__uzEl1E:qvL3-vMn3lw:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=spv__uzEl1E:qvL3-vMn3lw:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=spv__uzEl1E:qvL3-vMn3lw:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=spv__uzEl1E:qvL3-vMn3lw:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=spv__uzEl1E:qvL3-vMn3lw:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=spv__uzEl1E:qvL3-vMn3lw:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=spv__uzEl1E:qvL3-vMn3lw:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=spv__uzEl1E:qvL3-vMn3lw:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/spv__uzEl1E" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com0http://blog.ioshints.info/2012/05/virtual-networks-skype-analogy.htmltag:blogger.com,1999:blog-23021255.post-45468963778561450032012-05-11T07:14:00.000+02:002012-05-11T07:14:00.489+02:00<p>Stephen Hauser sent me an interesting question after the <a href="http://www.guidetonetworkfabrics.com/">Data Center fabric webinar I did with Abner Germanow from Juniper</a>:</p><blockquote class="cite">A common theme in your talks is that L2 does not scale. Do you mean that Transparent (Learning) Bridging does not scale due to its flooding? Or is there something else that does not scale?</blockquote><p>As is oft the case, I’m not precise enough in my statements, so let’s fix that first:</p><a href="http://blog.ioshints.info/2012/05/transparent-bridging-aka-l2-switching.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-4546896377856145003?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Xh59trj2kv4:dcijUG8PYO4:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Xh59trj2kv4:dcijUG8PYO4:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Xh59trj2kv4:dcijUG8PYO4:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Xh59trj2kv4:dcijUG8PYO4:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Xh59trj2kv4:dcijUG8PYO4:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Xh59trj2kv4:dcijUG8PYO4:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Xh59trj2kv4:dcijUG8PYO4:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Xh59trj2kv4:dcijUG8PYO4:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Xh59trj2kv4:dcijUG8PYO4:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/Xh59trj2kv4" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com2http://blog.ioshints.info/2012/05/transparent-bridging-aka-l2-switching.htmltag:blogger.com,1999:blog-23021255.post-33577805834914453892012-05-10T07:17:00.000+02:002012-05-10T07:17:00.068+02:00<p>Just prior to <a href="http://techfieldday.com/2012/nfd3/">Networking Field Day</a>, the merry band of geeks sat down with Chip Copper, Brocade’s Solutioneer (a job title almost as good as Packet Herder) to discuss the intricate details of VCS Fabric. The videos are well worth watching – the technical details are interesting, but above all, Chip is a fantastic storyteller.</p><a href="http://blog.ioshints.info/2012/05/brocade-vcs-fabric.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-3357780583491445389?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=0kWmEGUEbB8:Ljp1r30bwKw:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=0kWmEGUEbB8:Ljp1r30bwKw:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=0kWmEGUEbB8:Ljp1r30bwKw:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=0kWmEGUEbB8:Ljp1r30bwKw:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=0kWmEGUEbB8:Ljp1r30bwKw:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=0kWmEGUEbB8:Ljp1r30bwKw:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=0kWmEGUEbB8:Ljp1r30bwKw:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=0kWmEGUEbB8:Ljp1r30bwKw:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=0kWmEGUEbB8:Ljp1r30bwKw:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/0kWmEGUEbB8" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com4http://blog.ioshints.info/2012/05/brocade-vcs-fabric.htmltag:blogger.com,1999:blog-23021255.post-44514921159561566952012-05-09T08:06:00.000+02:002012-05-09T08:06:07.226+02:00<p><a href="http://www.cisco.com/en/US/docs/ios-xml/ios/sec_conn_dmvpn/configuration/15-2mt/sec-conn-dmvpn-tun-mon.html#GUID-E968E183-0022-4E8C-89A6-69AE3AE2AFF9">NHRP-based interface state control</a> is a fantastic feature that you can use for faster convergence of very large DMVPN networks (as explained in the <a href="http://www.ipspace.net/DMVPN_Designs">DMVPN Designs</a> webinar, you can also use it to solve some interesting backup scenarios). We tested it in a network with over 1000 spokes (using ASR1K as the hub router) using very short registration timeouts, and the CPU utilization of the NHRP process rarely exceeded a few percents.</p><a href="http://blog.ioshints.info/2012/05/nhrp-rate-limiting-can-hurt-your-dmvpn.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-4451492115956156695?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=dEBrc4wik4M:2OtJ2XtuUCI:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=dEBrc4wik4M:2OtJ2XtuUCI:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=dEBrc4wik4M:2OtJ2XtuUCI:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=dEBrc4wik4M:2OtJ2XtuUCI:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=dEBrc4wik4M:2OtJ2XtuUCI:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=dEBrc4wik4M:2OtJ2XtuUCI:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=dEBrc4wik4M:2OtJ2XtuUCI:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=dEBrc4wik4M:2OtJ2XtuUCI:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=dEBrc4wik4M:2OtJ2XtuUCI:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/dEBrc4wik4M" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com0http://blog.ioshints.info/2012/05/nhrp-rate-limiting-can-hurt-your-dmvpn.htmltag:blogger.com,1999:blog-23021255.post-76188806732521517442012-05-07T13:37:00.000+02:002012-05-07T13:37:30.473+02:00<p>Every data center network has a mixture of bridging (layer-2 or MAC-based forwarding, aka switching) and routing (layer-3 or IP-based forwarding); the exact mix, the size of L2 domains, and the position of L2/L3 boundary depend heavily on the workload ... and I would really like to understand what works for you in your data center, so please leave as much feedback as you can in the comments.</p><a href="http://blog.ioshints.info/2012/05/does-optimal-l3-forwarding-matter-in.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-7618880673252151744?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=3IdUtFqyslQ:p-n7c9sQJoU:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=3IdUtFqyslQ:p-n7c9sQJoU:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=3IdUtFqyslQ:p-n7c9sQJoU:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=3IdUtFqyslQ:p-n7c9sQJoU:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=3IdUtFqyslQ:p-n7c9sQJoU:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=3IdUtFqyslQ:p-n7c9sQJoU:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=3IdUtFqyslQ:p-n7c9sQJoU:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=3IdUtFqyslQ:p-n7c9sQJoU:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=3IdUtFqyslQ:p-n7c9sQJoU:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/3IdUtFqyslQ" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com17http://blog.ioshints.info/2012/05/does-optimal-l3-forwarding-matter-in.htmltag:blogger.com,1999:blog-23021255.post-67280039887017436752012-04-26T08:10:00.000+02:002012-04-26T08:10:00.913+02:00<p>The most popular post in March was the one describing my <a href="http://tools.ietf.org/html/draft-jdurand-bgp-security-00">BGP security Internet draft</a>. That’s good news – let’s hope you’ll all implement the recommended security measures. And here’s the top-10 list as reported by Google Analytics.</p><ul class="ListParagraph"><li><a href="http://blog.ioshints.info/2012/03/my-first-internet-draft-has-just-been.html">My first Internet Draft has just been published</a></li><li><a href="http://blog.ioshints.info/2012/03/stretched-layer-2-subnets-server.html">Stretched Layer-2 Subnets – The Server Engineer Perspective</a></li><li><a href="http://blog.ioshints.info/2012/03/openflow-perfect-tool-to-build-smb-data.html">OpenFlow: A perfect tool to build SMB data center</a></li><li><a href="http://blog.ioshints.info/2012/03/knowledge-and-complexity.html">Knowledge and Complexity</a></li><li><a href="http://blog.ioshints.info/2012/03/cisco-vmware-merging-virtual-and.html">Cisco &amp; VMware: Merging the Virtual and Physical NICs</a></li><li><a href="http://blog.ioshints.info/2012/03/mplsvpn-in-data-center-maybe-not-in.html">MPLS/VPN in the Data Center? Maybe not in the hypervisors</a></li><li><a href="http://blog.ioshints.info/2012/03/vxlan-and-evb-questions.html">VXLAN and EVB questions</a></li><li><a href="http://blog.ioshints.info/2012/03/grumpy-monday-hp-and-openflow.html">Grumpy Monday: HP and OpenFlow</a></li><li><a href="http://blog.ioshints.info/2012/03/do-we-really-need-stateless-transport.html">Do we really need Stateless Transport Tunneling (STT)</a></li><li><a href="http://blog.ioshints.info/2012/03/scalable-virtualized-automated-data.html">Scalable, Virtualized, Automated Data Center</a></li></ul><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-6728003988701743675?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Z-oND_t9rjs:wOqtzKULBWM:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Z-oND_t9rjs:wOqtzKULBWM:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Z-oND_t9rjs:wOqtzKULBWM:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Z-oND_t9rjs:wOqtzKULBWM:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Z-oND_t9rjs:wOqtzKULBWM:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Z-oND_t9rjs:wOqtzKULBWM:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Z-oND_t9rjs:wOqtzKULBWM:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Z-oND_t9rjs:wOqtzKULBWM:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Z-oND_t9rjs:wOqtzKULBWM:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/Z-oND_t9rjs" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com0http://blog.ioshints.info/2012/04/best-of-march-2012.htmltag:blogger.com,1999:blog-23021255.post-7979485815116368752012-04-25T13:37:00.001+02:002012-04-25T13:37:43.708+02:00<p>In this part of the <a href="http://www.ipspace.net/OpenFlow">OpenFlow webinar</a>, <a href="http://etherealmind.com/who-am-i/">Greg Ferro</a> talks about <a href="http://www.youtube.com/watch?v=NhpeNmenvyM">SDN and controller ecosystems</a>, including a great overview of potentially relevant SDN technologies, from venerable SNMP to NETCONF and OpenFlow (<a href="http://www.ipspace.net/OpenFlow">more information</a>, <a href="http://www.ipspace.net/Roadmap/Data_center_webinars">roadmap</a>, <a href="http://demo.ipspace.net/get/OpenFlow#Videos">videos</a> and <a href="http://demo.ipspace.net/get/OpenFlow#Download">PDFs</a>).</p><div class='separator'><iframe width="420" height="290" src="http://www.youtube.com/embed/NhpeNmenvyM?rel=0" frameborder="0" allowfullscreen></iframe></div><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-797948581511636875?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=UG37PVkURZA:Uavs5c_IG0I:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=UG37PVkURZA:Uavs5c_IG0I:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=UG37PVkURZA:Uavs5c_IG0I:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=UG37PVkURZA:Uavs5c_IG0I:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=UG37PVkURZA:Uavs5c_IG0I:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=UG37PVkURZA:Uavs5c_IG0I:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=UG37PVkURZA:Uavs5c_IG0I:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=UG37PVkURZA:Uavs5c_IG0I:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=UG37PVkURZA:Uavs5c_IG0I:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/UG37PVkURZA" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com1http://blog.ioshints.info/2012/04/video-sdn-and-controller-ecosystems.htmltag:blogger.com,1999:blog-23021255.post-11524367825122481552012-04-24T08:19:00.000+02:002012-04-24T08:19:00.420+02:00<p><a href="http://www.linkedin.com/pub/vasilis-bouloukos/2/a66/b69">Vasilis</a> sent me an interesting campfire story. It started with a common mistake:</p><blockquote class="cite">An external partner of my company used an Ethernet cable and connected two switchport interfaces of one of our access switches .</blockquote><p>Being a conscientious networking engineer, he had the usual safeguards in place ...</p><a href="http://blog.ioshints.info/2012/04/stp-loops-strike-again.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-1152436782512248155?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=CsQXF2Y0u-w:2952gnPhKMo:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=CsQXF2Y0u-w:2952gnPhKMo:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=CsQXF2Y0u-w:2952gnPhKMo:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=CsQXF2Y0u-w:2952gnPhKMo:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=CsQXF2Y0u-w:2952gnPhKMo:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=CsQXF2Y0u-w:2952gnPhKMo:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=CsQXF2Y0u-w:2952gnPhKMo:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=CsQXF2Y0u-w:2952gnPhKMo:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=CsQXF2Y0u-w:2952gnPhKMo:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/CsQXF2Y0u-w" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com31http://blog.ioshints.info/2012/04/stp-loops-strike-again.htmltag:blogger.com,1999:blog-23021255.post-71835285004890707872012-04-23T08:06:00.000+02:002012-04-23T08:06:00.307+02:00<p>Five years ago I was writing about trivial things like <a href="http://blog.ioshints.info/2007/04/continuous-ping-from-router.html">continuous pings,</a> <a href="http://blog.ioshints.info/2007/04/boot-2800-router-with-usb-image.html">booting a 2800-router with an USB image</a> and <a href="http://blog.ioshints.info/2007/04/execute-multiple-commands-at-once.html">EEM tricks</a>. Three years ago it was <a href="http://blog.ioshints.info/2009/04/traffic-shaping-in-cisco-ios.html">traffic shaping</a>, <a href="http://blog.ioshints.info/2009/04/ios-interface-names.html">IOS interface names</a>, OSPF (<a href="http://blog.ioshints.info/2009/04/ospf-router-id-selection-all-details.html">router ID selection </a>and <a href="http://blog.ioshints.info/2009/04/spf-events-in-ospf-and-is-is.html">SPF events</a>) and <a href="http://blog.ioshints.info/2009/04/bgp-route-reflector-update-groups.html">BGP Route Reflector update groups</a>.</p><a href="http://blog.ioshints.info/2012/04/3-5-years-ago-april-2012.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-7183528500489070787?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=7zpPmYHq8uM:2vjsKCb8GUU:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=7zpPmYHq8uM:2vjsKCb8GUU:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=7zpPmYHq8uM:2vjsKCb8GUU:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=7zpPmYHq8uM:2vjsKCb8GUU:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=7zpPmYHq8uM:2vjsKCb8GUU:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=7zpPmYHq8uM:2vjsKCb8GUU:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=7zpPmYHq8uM:2vjsKCb8GUU:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=7zpPmYHq8uM:2vjsKCb8GUU:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=7zpPmYHq8uM:2vjsKCb8GUU:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/7zpPmYHq8uM" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com0http://blog.ioshints.info/2012/04/3-5-years-ago-april-2012.htmltag:blogger.com,1999:blog-23021255.post-80841419140200066692012-04-21T07:51:00.000+02:002012-04-21T07:51:00.767+02:00<p>The blogosphere has been full of OpenFlow-related articles recently (no wonder - there was <a href="http://opennetsummit.org/">Open Networking Summit</a> in Santa Clara), so here&#39;s a special OpenFlow edition of interesting links</p><p>Let&#39;s start with my good friend <a href="http://etherealmind.com/">Greg Ferro</a>. I&#39;m so glad to see him returning back from a sabbatical at OpenFlow Kool-Aid lake. His latest articles are a must-read: <a href="http://etherealmind.com/openflow-might-lower-capex-while-sdn-will-increase-opex/">OpenFlow might lower CapEx while SDN will increase OpEx</a> and <a href="http://etherealmind.com/openflow-doesnt-undermine-vendors-even-though-it-changes-everything/">OpenFlow doesn’t undermine Vendors even though it changes everything</a>. We&#39;re perfectly aligned, which will make our discussions way less interesting, but I&#39;m glad I&#39;m not the only conservative in the town.</p><a href="http://blog.ioshints.info/2012/04/interesting-openflow-links-2012-04-21.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-8084141914020006669?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=FE7dVRcTYbI:eG8JK0PIveY:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=FE7dVRcTYbI:eG8JK0PIveY:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=FE7dVRcTYbI:eG8JK0PIveY:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=FE7dVRcTYbI:eG8JK0PIveY:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=FE7dVRcTYbI:eG8JK0PIveY:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=FE7dVRcTYbI:eG8JK0PIveY:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=FE7dVRcTYbI:eG8JK0PIveY:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=FE7dVRcTYbI:eG8JK0PIveY:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=FE7dVRcTYbI:eG8JK0PIveY:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/FE7dVRcTYbI" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com0http://blog.ioshints.info/2012/04/interesting-openflow-links-2012-04-21.htmltag:blogger.com,1999:blog-23021255.post-22639991777851100032012-04-20T07:30:00.000+02:002012-04-20T07:30:02.450+02:00<p>I’ve published <a href="http://demo.ipspace.net/get/CloudNet#PPT">two cloud networking-related presentations</a> to my <a href="http://demo.ipspace.net/bin/start">webinar demo web site</a>: the <a href="http://demo.ipspace.net/get/Cloud%20Computing%20Networking%20EuroNOG.pdf">Cloud Computing Networking Under the Hood</a> presentation from <a href="http://www.data.proidea.org.pl/euronog/1edycja/materialy/video/Ivan_Pepelnjak.mp4">EuroNOG 2011</a> briefly describes various technologies you can use to implement virtual networks in IaaS clouds, the <a href="http://demo.ipspace.net/get/Cloud%20Networking%20Scalability%20RIPE64.pdf">Cloud Networking Scalability</a> one from <a href="https://ripe64.ripe.net/archives/video/29/">RIPE64</a> addresses the scalability aspects of these technologies.</p><p>You can find a broader in-depth description of these topics in the <a href="http://www.ipspace.net/CloudNet">Cloud Computing Networking</a> webinar (<a href="http://cloudnetworking.eventbrite.com/">register for the next week’s live session</a>).</p><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-2263999177785110003?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=KjtUlD1v-bA:a3rCKLLyZ28:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=KjtUlD1v-bA:a3rCKLLyZ28:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=KjtUlD1v-bA:a3rCKLLyZ28:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=KjtUlD1v-bA:a3rCKLLyZ28:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=KjtUlD1v-bA:a3rCKLLyZ28:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=KjtUlD1v-bA:a3rCKLLyZ28:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=KjtUlD1v-bA:a3rCKLLyZ28:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=KjtUlD1v-bA:a3rCKLLyZ28:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=KjtUlD1v-bA:a3rCKLLyZ28:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/KjtUlD1v-bA" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com5http://blog.ioshints.info/2012/04/cloud-computing-networking.htmltag:blogger.com,1999:blog-23021255.post-39467745132892669732012-04-19T07:10:00.000+02:002012-04-19T07:10:00.100+02:00<p>VMware has a <a href="http://www.ntpro.nl/blog/archives/2024-vCloud-networking-explained-in-1-slide-and-52-animations.html">fantastic-looking cloud provisioning tool – vCloud director</a>. It allows cloud tenants to deploy their VMs and create new virtual networks with a click of a mouse (the underlying network has to provide a range of VLANs, or you could use <a href="http://blog.ioshints.info/2011/08/finally-mac-over-ip-based-vcloud.html">VXLAN</a> or <a href="http://blog.ioshints.info/2011/04/vcloud-director-networking.html">vCDNI</a> to implement the virtual segments). </p><p>Needless to say, when engineers not familiar with the networking intricacies create point-and-click application stacks without firewalls and load balancers, you get some interesting designs.</p><a href="http://blog.ioshints.info/2012/04/virtual-networking-is-more-than-vms-and.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-3946774513289266973?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8H4xH4DiinY:gxYYQpyOD-A:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8H4xH4DiinY:gxYYQpyOD-A:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8H4xH4DiinY:gxYYQpyOD-A:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8H4xH4DiinY:gxYYQpyOD-A:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=8H4xH4DiinY:gxYYQpyOD-A:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8H4xH4DiinY:gxYYQpyOD-A:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=8H4xH4DiinY:gxYYQpyOD-A:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=8H4xH4DiinY:gxYYQpyOD-A:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=8H4xH4DiinY:gxYYQpyOD-A:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/8H4xH4DiinY" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com7http://blog.ioshints.info/2012/04/virtual-networking-is-more-than-vms-and.htmltag:blogger.com,1999:blog-23021255.post-85961710678674767092012-04-18T07:54:00.000+02:002012-04-18T11:33:29.494+02:00<p>Google Analytics claims blog posts describing Nicira were among the most popular content written in February 2011. No surprise there. Here’s the whole top-10 list:</p><ul class="ListParagraph"><li><a href="http://blog.ioshints.info/2012/02/does-ccie-still-make-sense.html">Does CCIE still make sense?</a></li><li><a href="http://blog.ioshints.info/2012/02/nicira-open-vswitch-inside-vsphereesx.html">Nicira Open vSwitch inside vSphere/ESX</a></li><li><a href="http://blog.ioshints.info/2012/02/ibm-launched-nexus-1000v-competitor.html">IBM launched a Nexus 1000V competitor</a></li><li><a href="http://blog.ioshints.info/2012/02/nicira-bigswitch-nec-openflow-and-sdn.html">Nicira, BigSwitch, NEC, OpenFlow and SDN</a></li><li><a href="http://blog.ioshints.info/2012/02/nicira-uncloaked.html">Nicira uncloaked</a></li><li><a href="http://blog.ioshints.info/2012/02/6wind-solving-virtual-appliance.html">6WIND: Solving the Virtual Appliance Performance Issues</a></li><li><a href="http://blog.ioshints.info/2012/02/embrace-change-resistance-is-futile.html">Embrace the change ... resistance is futile ;)</a></li><li><a href="http://blog.ioshints.info/2012/02/microsoft-network-load-balancing-behind.html">Microsoft Network Load Balancing Behind the Scenes</a></li><li><a href="http://blog.ioshints.info/2012/02/edge-virtual-bridging-8021qbg.html">Edge Virtual Bridging (802.1Qbg) – a technology refusing to die</a></li><li><a href="http://blog.ioshints.info/2012/02/forwarding-state-abstraction-with.html">Forwarding State Abstraction with Tunneling and Labeling</a></li></ul><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-8596171067867476709?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=gCHf3efeK-0:qyN9m7fEf7M:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=gCHf3efeK-0:qyN9m7fEf7M:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=gCHf3efeK-0:qyN9m7fEf7M:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=gCHf3efeK-0:qyN9m7fEf7M:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=gCHf3efeK-0:qyN9m7fEf7M:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=gCHf3efeK-0:qyN9m7fEf7M:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=gCHf3efeK-0:qyN9m7fEf7M:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=gCHf3efeK-0:qyN9m7fEf7M:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=gCHf3efeK-0:qyN9m7fEf7M:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/gCHf3efeK-0" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com2http://blog.ioshints.info/2012/04/best-of-february-2011.htmltag:blogger.com,1999:blog-23021255.post-88507148513149521992012-04-17T13:02:00.000+02:002012-04-17T13:02:00.279+02:00<p>Buying a new networking appliance (be it VPN concentrator, firewall or load balancer … aka <a href="http://packetpushers.net/show-47-load-balancers-good-thing-we-step-in-it/">Application Delivery Controller</a>) is a royal pain. You never know how much performance you’ll need in two or three years (and your favorite bean counter will not allow you to scrap it in less than 4-5 years). You do know you’ll never get the performance promised in vendor’s data sheets … but you don’t always know which combination of features will kill the box.</p><p>Now, imagine someone offers you a <em>performance guarantee </em>– you’ll always get what you paid for. That’s what <a href="http://lineratesystems.com/">LineRate Systems</a>, a startup just exiting stealth mode is promising.</p><a href="http://blog.ioshints.info/2012/04/linerate-proxy-software-l4-7-appliance.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-8850714851314952199?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=LILG5sxn9AI:T6-7wqJcLOw:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=LILG5sxn9AI:T6-7wqJcLOw:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=LILG5sxn9AI:T6-7wqJcLOw:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=LILG5sxn9AI:T6-7wqJcLOw:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=LILG5sxn9AI:T6-7wqJcLOw:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=LILG5sxn9AI:T6-7wqJcLOw:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=LILG5sxn9AI:T6-7wqJcLOw:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=LILG5sxn9AI:T6-7wqJcLOw:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=LILG5sxn9AI:T6-7wqJcLOw:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/LILG5sxn9AI" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com16http://blog.ioshints.info/2012/04/linerate-proxy-software-l4-7-appliance.htmltag:blogger.com,1999:blog-23021255.post-14384864632596189502012-04-16T07:35:00.000+02:002012-04-16T09:18:18.244+02:00<p>One of the answers you get from some of the vendors selling you <em>data center fabrics </em>is “you can use any topology you wish” and then they start to rattle off an impressive list of buzzword-bingo-winning terms like <em>full mesh, </em><a href="http://en.wikipedia.org/wiki/Hypercube"><em>hypercube</em></a><em> </em>and <em>Clos fabric</em>. While <em>full mesh </em>sounds like a great idea (after all, what could possibly go wrong if every switch can talk directly to any other switch), it’s actually the worst possible architecture (apart from the fully randomized <a href="http://blog.ioshints.info/2012/04/monkey-design-still-doesnt-work-well.html">Monkey Design</a>).</p><p class="more">Before reading the rest of this post, you might want to visit <a href="http://packetpushers.net/the-sad-state-of-data-center-networking/"><em>Derick Winkworth’s The Sad State of Data Center Networking</em></a> to get in the proper mood.</p><a href="http://blog.ioshints.info/2012/04/full-mesh-is-worst-possible-fabric.html#more">Read more ...</a><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/23021255-1438486463259618950?l=blog.ioshints.info' alt='' /></div><div class="feedflare"> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Lpr0LZB7fQY:NMO8xJx4VPA:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=yIl2AUoC8zA" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Lpr0LZB7fQY:NMO8xJx4VPA:qj6IDK7rITs"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=qj6IDK7rITs" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Lpr0LZB7fQY:NMO8xJx4VPA:I9og5sOYxJI"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?d=I9og5sOYxJI" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Lpr0LZB7fQY:NMO8xJx4VPA:F7zBnMyn0Lo"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Lpr0LZB7fQY:NMO8xJx4VPA:F7zBnMyn0Lo" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Lpr0LZB7fQY:NMO8xJx4VPA:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Lpr0LZB7fQY:NMO8xJx4VPA:V_sGLiPBpWU" border="0"></img></a> <a href="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?a=Lpr0LZB7fQY:NMO8xJx4VPA:4cEx4HpKnUU"><img src="http://feeds.feedburner.com/~ff/CiscoIosHintsAndTricks?i=Lpr0LZB7fQY:NMO8xJx4VPA:4cEx4HpKnUU" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/CiscoIosHintsAndTricks/~4/Lpr0LZB7fQY" height="1" width="1"/>Ivan Pepelnjakhttp://www.blogger.com/profile/13457151406311272386noreply@blogger.com9http://blog.ioshints.info/2012/04/full-mesh-is-worst-possible-fabric.html