CiscoSteps

End to End Vlan

2011-12-13T10:51:00.001-08:00

VTP

2011-11-29T07:28:00.000-08:00

Before you add any switch to the network you need to get in the habit of checking the VTP configuration and make sure the VTP Configuration Revision number is set to 0. You can do this by console in to the switch and type in sho vtp status, if the revision is not 0 then do write erase and reload. This will put your switch to manufacture default. If you don’t do that and the Configuration Revision on your network switches is lower then your new switches your Vlan nodes will be down and you just created a big problem.

SW1#sho vtp status
VTP Version                     : 2
Configuration Revision          : 0
Maximum VLANs supported locally : 255
Number of existing VLANs        : 5
VTP Operating Mode              : Server
VTP Domain Name                 : ciscosteps
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Disabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00
Local updater ID is 0.0.0.0 (no valid interface found)

VTP Server:

Power to change vlan info
sends and receive VTP updates
saves Vlan config

======================================================

SW2#sho vtp status
VTP Version                     : 2
Configuration Revision          : 0
Maximum VLANs supported locally : 255
Number of existing VLANs        : 5
VTP Operating Mode              : Client
VTP Domain Name                 : ciscosteps
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Disabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00

VTP Client:

can't change vlan info
sends and receive VTP updates
does not save Vlan config

=======================================================

SW3#sho vtp status
VTP Version                     : 2
Configuration Revision          : 0
Maximum VLANs supported locally : 255
Number of existing VLANs        : 5
VTP Operating Mode              : Transparent
VTP Domain Name                 : ciscosteps
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Disabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0x7D 0x5A 0xA6 0x0E 0x9A 0x72 0xA0 0x3A
Configuration last modified by 0.0.0.0 at 0-0-00 00:00:00

VTP Transparent:

Power to change vlan info
forwards VTP updates
does not listen to VTP updates
saves Vlan config

configuring L3 etherChannel

2011-11-28T12:09:00.000-08:00

Configuring L3 ether-channel is almost the same as L2 the only exception is to add L3 protocol . To configure L3 on L2 switch you need to enable the port be a routed port otherwise you will not be able to add the ip address command to the interface .

Switch(config)#inter port-channel 12
Switch(config-if)#no switchport --> This command changes the interface from L2 to L3
Switch(config-if)#ip address 12.0.0.1 255.255.255.0
Switch(config-if)#no shut
Switch(config-if)#end
Switch#

Switch#ping 12.0.0.2--> the other ether-channel on SW2

Sending 5, 100-byte ICMP Echos to 12.0.0.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/5 ms

--------------------------------------------------------------------------

Switch#sho etherchannel
                Channel-group listing:
                ----------------------

Group: 12
----------
Group state = L2
Ports: 2 Maxports = 16
Port-channels: 1 Max Port-channels = 16
Protocol:   LACP
Switch#sho etherchannel summ
Switch#sho etherchannel summary
Flags: D - down        P - in port-channel
        I - stand-alone s - suspended
        H - Hot-standby (LACP only)
        R - Layer3      S - Layer2
        U - in use      f - failed to allocate aggregator
        u - unsuitable for bundling
        w - waiting to be aggregated
        d - default port

Number of channel-groups in use: 1
Number of aggregators:           1

Group Port-channel Protocol    Ports
------+-------------+-----------+----------------------------------------------

12     Po12(SU)           LACP   Fa0/1(P) Fa0/2(P)

--------------------------------------------------------------------------

Switch#sho interfaces etherchannel
FastEthernet0/1:
Port state    = 1
Channel group = 12          Mode = Active          Gcchange = -
Port-channel = Po12        GC   =   -             Pseudo port-channel = Po12
Port index    = 0           Load = 0x00            Protocol =   LACP

Flags: S - Device is sending Slow LACPDUs   F - Device is sending fast LACPDUs

        A - Device is in active mode.        P - Device is in passive mode.

Local information:
                            LACP port     Admin     Oper    Port        Port
Port      Flags   State     Priority      Key       Key     Number      State
Fa0/1     SA      down      32768         0x0       0x0     0x1

Partner's information:
                  LACP port                        Admin Oper   Port    Port
Port      Flags   Priority Dev ID          Age    key    Key    Number State
Fa0/1     SA      32768     00E0.B080.DED2         0x0    0x0    0x1

Age of the port in the current state: 00d:02h:10m:50s

FastEthernet0/2:
Port state    = 1
Channel group = 12          Mode = Active          Gcchange = -
Port-channel = Po12        GC   =   -             Pseudo port-channel = Po12
Port index    = 0           Load = 0x00            Protocol =   LACP

Flags: S - Device is sending Slow LACPDUs   F - Device is sending fast LACPDUs

        A - Device is in active mode.        P - Device is in passive mode.

Local information:
                            LACP port     Admin     Oper    Port        Port
Port      Flags   State     Priority      Key       Key     Number      State
Fa0/2     SA      down      32768         0x0       0x0     0x2

Partner's information:
                  LACP port                        Admin Oper   Port    Port
Port      Flags   Priority Dev ID          Age    key    Key    Number State
Fa0/2     SA      32768     00E0.B080.DED2         0x0    0x0    0x2

Age of the port in the current state: 00d:02h:10m:50s

----
Port-channel12:Port-channel12   (Primary aggregator)
Age of the Port-channel   = 00d:00h:30m:58s
Logical slot/port   = 2/12             Number of ports = 2
HotStandBy port = null
Port state          =
Protocol            =   1
Port Security       = Disabled

Ports in the Port-channel:

Index   Load   Port     EC state        No of bits
------+------+------+------------------+-----------
0     00     Fa0/1    Active             0
0     00     Fa0/2    Active             0
Time since last port bundled:    00d:02h:10m:50s    Fa0/2

configuring L2 etherChannel

2011-11-28T11:11:00.000-08:00

As you will see here, to utilize all the bandwidth, we created L2 ether-channel by combining both links and the commands to do that are the following:

Switch#config t
Switch(config)#int range fa0/1 - 2
Switch(config-if-range)#channel-protocol ?

lacp Prepare interface for LACP protocol
pagp Prepare interface for PAgP protocol

Switch(config-if-range)#channel-protocol lacp
Switch(config-if-range)#channel-group 12 ?

mode Etherchannel Mode of the interface

Switch(config-if-range)#channel-group 12 mode ?

active        Enable LACP unconditionally
auto      Enable PAgP only if a PAgP device is detected
desirable Enable PAgP unconditionally
on            Enable Etherchannel only
passive    Enable LACP only if a LACP device is detected

Switch(config-if-range)#channel-group 12 mode active ?
<cr>
Switch(config-if-range)#channel-group 12 mode active

%LINK-5-CHANGED: Interface Port-channel 12, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel 12, changed state to up
Switch(config-if-range)#end

------------------------------------------------------------------------------------

Switch#sho ip int b | inc up

Interface              IP-Address      OK? Method Status                Protocol

FastEthernet0/1        unassigned      YES unset up                    up

FastEthernet0/2        unassigned      YES unset up                    up

Port-channel 12        unassigned      YES unset up                    up

Switch#

Switch#sho etherchannel
                Channel-group listing:
                ----------------------

Group: 12
----------
Group state = L2
Ports: 2 Maxports = 16
Port-channels: 1 Max Port-channels = 16
Protocol:   LACP

------------------------------------------------------------------------------------

Switch#sho etherchannel port-channel
                Channel-group listing:
                ----------------------

Group: 12
----------
                Port-channels in the group:
                ---------------------------

Port-channel: Po12    (Primary Aggregator)
------------

Age of the Port-channel   = 00d:00h:17m:39s
Logical slot/port   = 2/12      Number of ports = 2
GC                  = 0x00000000      HotStandBy port = null
Port state          = Port-channel
Protocol            =   LACP
Port Security       = Disabled

Ports in the Port-channel:

Index   Load   Port     EC state        No of bits
------+------+------+------------------+-----------
0     00     Fa0/1    Active             0
0     00     Fa0/2    Active             0
Time since last port bundled:    00d:00h:15m:41s    Fa0/2
Switch#

Spanning Tree

2011-11-28T10:44:00.000-08:00

This is the spanning tree at its best , it is enable by default , once the spanning tree detect a loop on the topology it will block one of the port to prevent a loop. we can do show spanning-tree command to check.

Switch#sho spanning-tree
VLAN0001
Spanning tree enabled protocol ieee
Root ID    Priority    32769
             Address     00D0.5825.5C01
             Cost        19
             Port        1(FastEthernet0/1)
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority    32769 (priority 32768 sys-id-ext 1)
             Address     00E0.B080.DED2
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
             Aging Time 20

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/2            Altn BLK 19        128.2    P2p
Fa0/1            Root FWD 19        128.1    P2p

Basic Vlan config

2011-11-28T07:02:00.000-08:00

Switch>en
Switch#config t
Switch(config)#int fa0/12
Switch(config-if)#switchport mode access
Switch(config-if)#switchport access vlan 12
% Access VLAN does not exist. Creating vlan 12
Switch(config-if)#int fa0/13
Switch(config-if)#switchport mode access
Switch(config-if)#switchport access vlan 13
% Access VLAN does not exist. Creating vlan 13

------------------------------------------------------------------

Switch>en
Switch#config t
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#int fa0/1
Switch(config-if)#switchport mode trunk
Switch(config-if)#end
Switch#
Switch#sho interfaces trunk
Port        Mode         Encapsulation Status        Native vlan
Fa0/1       on           802.1q         trunking      1

Port        Vlans allowed on trunk
Fa0/1       1-1005

Port        Vlans allowed and active in management domain
Fa0/1       1,12,13

Port        Vlans in spanning tree forwarding state and not pruned
Fa0/1       1,12,13

-------------------------------------------------------------------

Switch#sho vlan

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/2, Fa0/3, Fa0/4, Fa0/5
                                                Fa0/6, Fa0/7, Fa0/8, Fa0/9
                                                Fa0/10, Fa0/11, Fa0/14, Fa0/15
                                                Fa0/16, Fa0/17, Fa0/18, Fa0/19
                                                Fa0/20, Fa0/21, Fa0/22, Fa0/23
                                                Fa0/24, Gig1/1, Gig1/2
12   VLAN0012                         active    Fa0/12
13   VLAN0013                         active    Fa0/13
1002 fddi-default                     act/unsup
1003 token-ring-default               act/unsup
1004 fddinet-default                  act/unsup
1005 trnet-default                    act/unsup

Static NAT

2011-10-18T14:12:00.000-07:00

Router Redundancy - HSRP-

2011-09-24T11:57:00.000-07:00

OSPF LSA Types

2011-07-26T12:42:00.000-07:00

Type 1 LSA - it build the graph for intra-area SPF

Describe their connected links
What are the cost of the links
What are the neighbors that are adjacent on the links

TO VERIFY : sho ip ospf database router [id]

Type 2 LSA - Generated by DR on broadcast and non broadcast network type

Not flooded outside the area they originated in :
The LSA will not move to the ABR

TO VERIFY : sho ip ospf database NETWORK [link ID] for DR

Type 3 LSA - Generated by ABR to summarize the topology to move traffic from area 0 to area 1 with out running SPF

example :
ABR can reach link 1 via SPF w/ the cost of 50
I can reach the ABR via SPF of 10 in my area
to reach link 1 via SPF in cost of 50+10 . this why inter-area is called DV (DISTANCE VICTOR)

TO VERIFY : sho ip ospf database summary [link ID]

Type 4 LSA - ASBR summary - Generated by ABR and describes the ABR reach-ability to ASBR, it does include cost but hides ABR's as actual path to destination

ABR can reach ASBR via SPF w/ the cost of 50
I can reach the ABR via SPF of 10 in my area
I can reach ASBR via SPF in cost of 50+10 this why intra-area is called DV (DISTANCE VICTOR)

TO VERIFY : sho ip ospf database asbr-summary [link ID]

Type 5 LSA - Generated by ASBR and describe routes the ASBR is redistributing

example: R1 run SPF cost of 5 to reach ABR, ABR runs SPF of 10 to reach ASBR, ASBR run cost of 15 to reach external route
R1's one cost to reach the external is 5+10+15

so if you look @ the topology LSA type 4 describe how to reach the ASBR and type 5 LSA provide the cost to the outside network

TO VERIFY : sho ip ospf database external [link ID]

DR / BDR / DROther

2011-07-23T13:16:00.000-07:00

Desinated Router ( DR )

used on broadcast links to minimize adjacencies and LSA replication

Backup Designated Router ( BDR )

Used for redundancy of DR

DROthers

For all other routers on the network
form adjacency w/ DR & BDR
Stop at 2-way adjacency with each other

The DR and BDR are chosen through election process

DROther send LSUs to DR/BDR via multicast 224.0.0.6

DR forwards LSUs to DROthers via multicast 224.0.0.5

Prevents repeated forwarding of unneeded LSAs on the network

BDR does not forward LSUs , it only waits for DR to fail

OSPF Network Types

2011-07-23T12:53:00.000-07:00

Broadcast ==> Ethernet
Non Broadcast ===> ATM or Frame-relay
Point - to - Point ===> HDLC or PPP
Point-to-Multipoint ===> work around for ATM and Frame-relay design
Point-to-Multipoint Non Broadcast ===> work around for ATM and Frame-relay design
loopback ==> used for software loopbacks

OSPF Stub area, totally stubby and NSSA

2011-06-09T13:51:00.000-07:00

multiple-area OSPF on a router

this is standard ospf out put from sho ip osp neighbor and router and if you look at R2 they are no inter-area routes

Now we are Using configure a OSPF are 23 as a STUB and do the show ip ospf on R2. As you see area 23 now is shows as stub area . Lets do a show ip route command on R3, you can see that R3 now has a default route pointing toward R2. A stub area does not receive any external routes. It receives a default route and OSPF inter-area routes.

The command to configure stubby area is as follow:

R2(config)# router ospf 1
R2(config-router)# area 23 stub
R3(config)# router ospf 1
R3(config-router)# area 23 stub

On R2 we are going to do show ip ospf database to examine the LSA's. As you see we have only 2 LAS's for each area.

In this next senario we configured OSPF as totally stubby area , look at the out put of sho ip ospf database and look at the LSA for area 23 . you see that the default route was injected and when you issue the command sho ip route you can only see the incoming route from ospf .

The command to configure totally stubby areais as follow:

Enter the stub no-summary command on R2 (the ABR) under the OSPF process.
R2(config)# router ospf 1
R2(config-router)# area 23 stub no-summary

Now will discus NSSA.

To generate an external route into the NSSA, use the redistribute connected subnets command on R3. This adds the previously unreachable loopback 20 into OSPF. Be sure to include the subnets keyword; otherwise, only classful networks are redistributed.

R2(config)# router ospf 1
R2(config-router)# no area 23 stub
R2(config-router)# area 23 nssa

R3(config)# router ospf 1
R3(config-router)# no area 23 stub
R3(config-router)# area 23 nssa
R3(config-router)# redistribute connected subnets
after the config on R2 and R3 as ASSA we come up w/ the following out out when sho ip osp command is typed on R2 (it will be the same on R3) :

Nlet look at routing table for each router and see what happen . lets type show ip route on R2. Notice that the external route comes in as type N2 from R3. This is because it is a special NSSA external route

Now lets do show ip route output on R1. Notice that the route is now a regular E2 external route, because R2 has performed the type 7 to type 5 translation and R3 no longer has a default route in it, but inter-area routes are coming in.
Note: An NSSA does not have the default route injected by the ABR (R2) automatically. It is possible to make the ABR inject the default route into the NSSA using the area 23 nssa default-information-originate command on R2

Route Summarization Calculation Example

2011-06-06T07:03:00.000-07:00

Networks to summarize :We are using /24

172.16.8.0
172.16.9.0
172.16.10.0
172.16.11.0
172.16.12.0
172.16.13.0
172.16.14.0
172.16.15.0
172.16.16.0
172.16.17.0
172.16.18.0
172.16.19.0

first we need addresses converted to binary format:
(in this example the changes occurs on the 3rd octet )

00001000 =8
00001001 =9
00001010 =10
00001011 =11
00001100 =12
00001101 =13
00001110 =14
00001111 =15
00010000 =16
00010000 =17
00010001 =18
00010011 =19

we need to locate the ON=1 bits at which the common pattern of digits ends
00001|000 =8
00001|001 =9
00001|010 =10
00001|011 =11
00001|100 =12
00001|101 =13
00001|110 =14
00001|111 =15
0001|0000 =16
0001|0000 =17
0001|0001 =18
0001|0011 =19

Now lets look for summary address(es) !!!

00001 = 8
0001 = 16

now let put this 2 numbers on the 3rd octet of the Ip
AHA !!! we have 2 summary addresses
172.16.8.0 and 172.16.16.0

Now we need to find out the subnet masks for this 2 Ip.
Locate the bit where the common pattern of digits ends for the 2 Ips.

00001|000 =8
00001|001 =9
00001|010 =10
00001|011 =11
00001|100 =12
00001|101 =13
00001|110 =14
00001|111 =15

000100|00 =16
000100|00 =17
000100|01 =18
000100|11 =19

The first 21 bits of the IP addresses from 172.16.8.0 through 172.16.15.0 Therefore /21
The first 22 bits of the IP addresses from 172.16.16.0 through 172.16.19.0 Therefore /22.

And we use this value as a 3rd octet in our net-mask

So :

172.16.8.0 255.255.248.0
172.16.16.0 255.255.252.0

Its our summarized routes / networks.

OSPF Point-to-Multipoint

2011-05-29T12:11:00.000-07:00

What we have here is an OSPF network on non broadcast, by default when you configure the frame relay interfaces, all of them will be in network type NON BROADCAST. We also left the OSPF priority on the interfaces to default. As you see the router with highest Ip wins to be a DR.

In the second scenario we only going to use the OSPF Point to Multipoint command on R2 and see what is the behavior of the network. All frame relay interfaces are in default priority and watch the adjacency

In the third scenario we only going to use the ospf point to multipoint command on all the 3 interfaces and see what the behavior of the network is this time and watch the adjacency. All frame relay interfaces are in default priority

OSPF config On None Broadcast Mode over Frame-Relay

2011-05-28T10:35:00.000-07:00

All 3 routers are using the default none broadcast mode on their frame-relay interfaces, so neighboring routers must be manually configured on DR, in this case is R1. We manually changed the OSPF priority on the interface level with the command ip ospf priority 0 on R2 and R3 so router 1 can become a DR

As you see here all 3 routers formed adjacency and R1 was chosen as DR

OSPF config On Broadcast Mode over Frame-Relay

2011-05-28T09:16:00.000-07:00

All 3 routers are using a broadcast statement on the interface level by typing a command Ip ospf network broadcast this way the ospf adjacency will form on their frame-relay interfaces, We manually changed the OSPF priority on the interface level with the command ip ospf priority 0 on R2 and R3 and that resulted of R1 to become a DR

OSPF basic topology and config

2011-05-25T10:46:00.000-07:00

Our topology here is point to point with OSPF AS 24 and all the router belongs to Area 0 with class C IP.

On Point – Point connection topology the OSPF adjacency state is Full, There is no DR or BDR.
sho ip ospf nei will show routers that form adjacency

Here on show ip ospf database command as you see the sequence number is the same , this sequence number is a 32 bit that start from 0x8000001 to 0x7FFFFFF , The larger the number the recent the LSA is. To ensure an accurate database, OSPF floods each LSA every 30 min and it called LSRefresh with the max of 60 min (it shows in sec in the router).

frame relay topology and config

2011-05-18T12:37:00.000-07:00

Configuring and Troubleshooting Cisco WAN Lines

2011-05-17T10:57:00.000-07:00

Ciscosteps#card type T1 0 0

Ciscosteps#config t

Ciscosteps(config)#Interface serial 0/0
Ciscosteps(config-if)#service-module t1 clock source internal
Ciscosteps(config-if)#service-module t1 timeslots 1-24 speed 64
Ciscosteps(config-if)#service-module t1 framing esf
Ciscosteps(config-if)#service-module t1 linecode b8zs
Ciscosteps(config-if)#ip address x.x.x.x 255.x.x.x

Ciscosteps(config-if)#encapsulation ????
Ciscosteps(config-if)#fair-que
Ciscosteps(config)#no shut

Troubleshooting Cisco WAN Lines

Common WAN Issues fall into these categories:

· Circuit is down

· Circuit is in loop

· Circuit is taking errors

WAN interface problems can be identified by the status line of the show interfaces serial display. See table below.

Serial Lines: show interfaces serial Status Line Conditions

Status Line Condition	Possible Problem	Solution
Serial x is up, line protocol is up	None	This is the proper status line condition. No action is required
Serial x is up, line protocol is up (looped)	A loop exists in the circuit. The sequence number in the keepalive packet changes to a random number when a loop is initially detected. If the same random number is returned over the link, a loop exists.	Reset the CSU/DSU, and inspect the line status. If the line protocol comes up, no other action is needed. If not, contact the leased-line or other carrier service for line troubleshooting assistance.
Serial x is up, line protocol is down	A high error rate has occurred due to a telephone company service problem. A CSU/DSU or Router (interface) hardware problem has occurred	Loop CSU/DSU (DTE loop). If the problem continues, it is likely that there is a hardware problem. Swap out bad hardware; (CSU/DSU, cabling, router port) If the problem does not continue, it is likely that there is a telephone company problem.
Serial x is down, line protocol is down	The router is not sensing a carrier signal (that is, the CD is not active). A telephone company problem has occurred—line is down or is not connected to CSU/DSU. Cabling is faulty or incorrect. Hardware failure has occurred (CSU/DSU).	Check the LEDs on the CSU/DSU to see whether the CD is active. Verify that you are using the proper cable and interface. Contact your leased-line or other carrier service to see whether there is a problem. Swap faulty parts. If you suspect faulty router hardware, change the serial line to another port. If the connection comes up, the previously connected interface has a problem.

CSU and DSU Loopback Tests

If the output of the show interfaces serial exec command indicates that the serial line is up but the line protocol is down, use the CSU/DSU loopback tests to determine the source of the problem. Perform the local loop test first, and then perform the remote test

The use of extended ping tests can be a great method to generate traffic & verify condition of the circuit.

Step 1 Put the CSU/DSU into local loopback mode.

Step 2 Configure the extended ping command to send different data patterns and packet sizes. (all-zeros 1500-byte ping and an all-ones 1500-byte ping) respectively.

Step 3 Examine the show interfaces serial command output and determine whether input errors have increased. If input errors have not increased, the local hardware (DSU, cable, router interface card) is probably in good condition. Assuming that this test sequence was prompted by the appearance of a large number of CRC and framing errors, a clocking problem is likely.

Step 4 If you determine that the clocking configuration is correct and is operating properly, put the CSU/DSU into remote loopback mode.

Step 5 Repeat the ping test and look for changes in the input error statistics.

Step 6 If input errors increase, there is a problem either in the serial line or on the CSU/DSU. Contact the WAN service provider and troubleshoot as necessary.

Ciscosteps# ping

Protocol [ip]:

Target IP address: 10.10.10.1

Repeat count [5]: 1000

Datagram size [100]: 1500

Timeout in seconds [2]:

Extended commands [n]: yes

Source address:

Type of service [0]:

Set DF bit in IP header? [no]:

Validate reply data? [no]:

Data pattern [0xABCD]: 0x0000

Loose, Strict, Record, Timestamp, Verbose[none]:

Sweep range of sizes [n]:

Data pattern Options:

- all zero’s: 0x0000

- all one’s: 0xffff

Show Interfaces Serial Field Descriptions (continued)

EIGRP Metric

2011-05-15T11:02:00.000-07:00

Dual selects routes based on 5 composite metrics, but by default it only uses 2 (Bandwidth and Delay).

To choose the desired destination to R 5 dual will choose the path with lowest Metric.

Bandwidth + Delay= lowest Metric

Bandwidth = (10^7/least Bw)*256

Delay= (total delay)*256

The formula is (10^7/least Bw)*256 + Total Delay*256

R1-->R2 -->R5

Least Bandwidth to R5 = 64 KBPS

Total Delay = 4000*256

Bandwidth = (10^7/least Bw)*256 = (10,000,000/64)*256= 40,000,000

Delay= (2000+2000)*256=1024000

Eigrp Metric calculation =40,000,000 + 1024000= 41024000

R1-->R3-->R4>R5

Least Bandwidth to R5 = 64 KBPS

Total Delay = 6000*256

Bandwidth = (10^7/least Bw)*256 = (10,000,000/64)*256= 40,000,000

Delay= (2000+2000+2000)*256= 1536000

Eigrp Metric calculation = 40,000,000 + 1536000= 41536000

Router R1 therefore choose the lower path with the Metric of 41024000

Eigrp authentication

2011-05-11T10:55:00.000-07:00

Eigrp Ip route

2011-05-09T08:41:00.000-07:00

R1#sho run

hostname R1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
memory-size iomem 5
!
ip cef
no ip domain lookup
!
interface Serial0/0
ip address 1.1.1.1 255.0.0.0
serial restart-delay 0
!
interface Ethernet1/0
ip address 10.1.1.1 255.0.0.0
half-duplex
!
router eigrp 100
network 1.0.0.0
network 10.0.0.0
no auto-summary
!
no ip http server
no ip http secure-server
!
control-plane
!

!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
!
!
end

R2# sho run

hostname R2

boot-start-marker

boot-end-marker

no aaa new-model

memory-size iomem 5

ip cef

no ip domain lookup

interface Serial0/0

ip address 2.2.2.1 255.0.0.0

serial restart-delay 0

interface Serial0/1

ip address 1.1.1.2 255.0.0.0

serial restart-delay 0

interface Ethernet1/0

ip address 20.1.1.1 255.0.0.0

half-duplex

router eigrp 100

network 1.0.0.0

network 2.0.0.0

network 20.0.0.0

no auto-summary

no ip http server

no ip http secure-server

ip default-network 2.0.0.0

ip route 30.0.0.0 255.0.0.0 2.2.2.2

control-plane

line con 0

exec-timeout 0 0

logging synchronous

line aux 0

line vty 0 4

end

R3#sho run

hostname R3

boot-start-marker

boot-end-marker

no aaa new-model

memory-size iomem 5

ip cef

no ip domain lookup

interface Serial0/2

ip address 2.2.2.2 255.0.0.0

serial restart-delay 0

interface Ethernet1/0

ip address 30.1.1.1 255.0.0.0

half-duplex

router eigrp 100

network 2.0.0.0

no auto-summary

no ip http server

no ip http secure-server

control-plane

line con 0

exec-timeout 0 0

logging synchronous

line aux 0

line vty 0 4

end

R1#   sho ip route

Gateway of last resort is 1.1.1.2 to network 2.0.0.0

C    1.0.0.0/8 is directly connected, Serial0/0
D*   2.0.0.0/8 [90/2681856] via 1.1.1.2, 02:21:05, Serial0/0
D    20.0.0.0/8 [90/2195456] via 1.1.1.2, 03:36:37, Serial0/0
C    10.0.0.0/8 is directly connected, Ethernet1/0

R1#sho ip route eigrp
D*   2.0.0.0/8 [90/2681856] via 1.1.1.2, 02:22:47, Serial0/0
D    20.0.0.0/8 [90/2195456] via 1.1.1.2, 03:38:19, Serial0/0

DUAL EIGRP Terminology

2011-05-07T09:37:00.000-07:00

DUAL EIGRP Terminology

· Selects lowest-cost, loop-free paths to each destination

· AD = cost between the next-hop router and the destination

· FD = cost from local router = AD of next-hop router + cost between the local router and the next-hop router

· Lowest-cost = lowest FD

· (Current) successor = next-hop router with lowest-cost, loop free path

· Feasible successor = backup router with loop-free path (AD of feasible successor must be less than FD of current successor route)

R1#sho ip eigrp topology

IP-EIGRP Topology Table for AS(100)/ID(10.1.1.1)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,

r - reply Status, s - sia Status

P 10.3.3.0/24, 1 successors, FD is 332800

FD= cost b/w r1 & r3 AD= cost b/w r2 & r3

via 10.1.1.2 (332800/307200), FastEthernet0/0

P 10.2.2.0/24, 1 successors, FD is 307200

via 10.1.1.2 (307200/281600), FastEthernet0/0

P 10.1.1.0/24, 1 successors, FD is 281600

via Connected, FastEthernet0/0

A successor is a neighboring router that has a least-cost path to

a destination (the lowest FD)

DUAL also keeps backup paths to each destination in case the successor is no longer available and its called feasible successor. To qualify as a feasible successor, a next-hop router must have an AD less than the FD of the current successor route

EIGRP Neighbors

2011-05-06T08:02:00.000-07:00

IP EIGRP Neighbors

When a router discovers and forms an adjacency with a new neighbor, it records the neighbor’s address and the interface through which it can be reached as an entry in the neighbor table.

R1>en

R1#config t

Enter configuration commands, one per line. End with CNTL/Z.

R1(config)#int f0/0

R1(config-if)#ip address 10.1.1.1 255.255.255.0

R1(config-if)#no shut

R1(config-if)#exit

R1(config)#router eigrp 100

R1(config-router)#network 10.2.2.0

R1(config-router)#no auto-summary

R1(config-router)#end

R1#wr

R3>en

R3#config t

Enter configuration commands, one per line. End with CNTL/Z.

R3(config)#int fa0/1

R3(config-if)#ip address 10.2.2.2 255.255.255.0

R3(config-if)#no shut

R3(config-if)#exit

R3(config)#router eigrp 100

R3(config-router)#network 10.1.1.1

R3(config-router)#no auto-summary

R3(config-router)#end

R3#wr

R2>en

R2#confi t

R2(config)#int fa0/0

R2(config-if)#ip address 10.1.1.2 255.255.255.0

R2(config-if)#no shut

R2(config-if)#exit

R2(config)#router eigrp 100

R2(config-router)#network 10.2.2.0

R2(config-router)#end

R2#

R2#config t

R2(config)#int fa0/1

R2(config-if)#ip address 10.2.2.1 255.255.255.0

R2(config-if)#no shut

R2(config-if)#exit

R2(config)#router eigrp 100

R2(config-router)#no auto-summary

R2(config-router)#exit

R2#wr

R2#sho ip eigrp ne

IP-EIGRP neighbors for process 100

H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num

1 10.2.2.2 Fa0/1 11 00:00:22 36 216 0 3

0 10.1.1.1 Fa0/0 12 00:02:33 82 492 0 3

H = this list the order in which the peering session was established with specified neighbor

Address = the neighbors’ address in this example 10.2.2.2 and 10.1.1.1

Interface = the interface on this router trough witch it is receiving hello packet. in this example R2

Hold time= the maximum time in seconds the router will wait before it will declare the neighbor unavailable

up time = H:min:sec since the local router first heard from the neighbor

SRTT= Smooth Round Trip Timer- the time that will take for the packet to reach the neighbor and back to local router for acknowledgement in MILLISECONDS

RTO= the time the router waits for acknowledgement before retransmitting a reliable packet to the neighbor

Q = queue count, the number of (update, query and replay) waiting in the queue to be sent out. if > then 0 then there is a problem.

Seq = sequence number of the last update received from the neighbor

T3 loopback Barrel

2010-08-15T19:25:00.000-07:00