Technical Certifications

IS-IS Authentication

2011-12-31T14:04:00.002-05:00

Here is a link on youtube for better viewing.

Change IS-IS Router Type

2011-12-29T17:19:00.001-05:00

Here is a link for easier viewing.

Configure Integrated IS-IS

2011-12-29T13:14:00.007-05:00

Here is the youtube link for better viewing.

CCIE SP BGP "always-compare-med" vs. "deterministic-med"

2011-12-15T15:58:00.001-05:00

There are two BGP configuration commands that can influence the MED-based path selection, the bgp deterministic-med and the bgp always-compare-med commands.

Enabling the bgp deterministic-med command ensures the comparison of the MED variable when choosing routes advertised by different peers in the same autonomous system. Enabling the bgp always-compare-med command ensures the comparison of the MED for paths from neighbors in different autonomous systems. The bgp always-compare-med command is useful when multiple service providers or enterprises agree on a uniform policy for setting MED.

Note: The bgp deterministic-med and bgp always-compare-med commands are not enabled by default. Also, the two commands are separate; enabling one does not automatically enable the other

CISSP New Book

2008-02-27T12:17:00.001-05:00

There is a new 4th Edition CISSP book:

IP Precedence Values

2008-02-22T10:20:00.001-05:00

0 : Routine
1 : Priority
2 : Immediate
3 : Flash
4 : Flash Override
5 : Critical
6 : Internet
7 : Network

Juniper Certifications

2008-02-12T07:42:00.001-05:00

Although, I have used this blog to focus mainly on Cisco and CISSP certifications, I have also worked on Juniper Networks certifications. I personally feel that having Juniper networks skills will help tremendously in the I.T. field. Anyway, I was on Juniper's site when I came across a list of network resources that you'll find extremely helpful not only in acheiving certifications but in everyday work.

Default Administrative Distance Value Table

2007-12-27T14:14:00.000-05:00

This table lists the administrative distance default values of the protocols that Cisco supports:

Connected interface - 0

Static route - 1

Enhanced Interior Gateway Routing Protocol (EIGRP) summary route - 5

External Border Gateway Protocol (BGP) - 20

Internal EIGRP - 90

IGRP - 100

OSPF - 110

Intermediate System-to-Intermediate System (IS-IS) - 115

Routing Information Protocol (RIP) - 120

Exterior Gateway Protocol (EGP) - 140

On Demand Routing (ODR) - 160

External EIGRP - 170

Internal BGP - 200

Unknown* - 255

SIP Response Messages

2007-10-01T11:09:00.000-04:00

SIP response messages are very similar to HTTP server response messages:

1xx Response - Information responses

2xx Response - Successful responses

3xx Response - Redirection responses

4xx Response - Request failure responses

5xx Response - Server failure responses

6xx Response - Global responses

Cisco Queuing Techniques

2007-09-18T11:09:00.000-04:00

Some basic queuing techniques available on cisco devices:

1. FIFO - this is the simplest algorithm; basically "First-In, First-Out"

2. PQ - Priority Queuing allows for the prioritization of traffic but can cause queue starvation because the top priority queue is always serviced first.

3. RR - Round-robin uses multiple queues to provide equal access to all queues but offers no prioritization.

4. WRR - Weighted-round-robin is a round-robin queue that allows for priority queues. however, but some implementations don't provide the correct bandwidth allocation because of the way bytes are counted. In cisco terms, CQ (custom queuing) is an implementation of WRR, allowing for up to 16 queues for traffic classification

5. DRR - Deficit round robin solves the problem of WRR by keeping a "deficit" county that subtracts during the following cycle any extra bytes received during the previous cycle. This is only available on the cisco 12000 series routers.

Types of QoS Models

2007-08-20T15:52:00.000-04:00

Three different models exist for implementing quality of service (QoS) on a network:

1. Best-Effort model

2. Integrated Services (IntServ) model

3. Differentiated Services (DiffServ) model

If QoS policies are not implemented, traffic is forwarded using the Best-Effort model.

Biometric Effectiveness

2007-08-08T10:57:00.000-04:00

From a security standpoint, here is the order of effectiveness for biometric techniques (most effective listed first):

1. Iris Scan

2. Retina Scan

3. Fingerprint

4. Hand Geometry

5. Voice Pattern

6. Keystroke Pattern

7. Signature

Bell-Lapadula vs. Biba, Key Elements

2007-07-28T11:42:00.001-04:00

Here are some tips for remembering details about the Bell-Lapadula and Biba security models. The B-L model is used to provide confidentiality, whereas the Biba model is used to provide integrity. When you see the word "simple", it applies to reading. If the rules uses * or "star", the rule is talking about writing.

In summary:

Bell-Lapadula - CONFIDENTIALITY
Biba - INTEGRITY
"simple" = reading
* or "star" = writing

Biba Security Model Main Rules

2007-07-28T11:16:00.000-04:00

1. * - Integrity Axiom - A subject cannot write data to an object at a higher integrity level. This is known as "No write up".

2. Simple Integrity Axiom - A subject cannot read data from a lower integrity level. This is known as "No read down".

Bell-LaPadula Security Model Main Rules

2007-07-26T09:50:00.000-04:00

1. Simple Security Rule - A subject cannot read data within an object that resides at a higher security level. This is known as "No read up".

2. * - Property Rule - A subject cannot write to an object at a lower security level. This is known as "No write down".

3. Strong Star Property Rule - For a subject to be able to read and write to an object, the subject's clearance and the object's classification must be equal.

Six Major VoIP Protocols

2007-07-20T12:34:00.000-04:00

H.323 - ITU standard protocol for interactive conferencing

MGCP (Media Gateway Control Protocol) - a method of PSTN gateway control or thin device control

Megaco/H.248 - joint IETF/ITU standard protocol that provides full call control intelligence

SIP (Session Initiation Protocol) - a protocol that specifies commands and responses to set up and tear down calls (end-to-end call signaling); text based

RTP (Real-time Transport Protocol) - an IETF media streaming protocol

RTCP (Read-time Transport Control Protocol) - provies out-of-band control information for an RTP flow

7 Layers of OSI Model

2007-07-20T08:00:00.000-04:00

There are 7 layers of the OSI Model. I remember them using the phrase "All People Seem To Need Data Processing". There are others. Freel free to comment on them. Here they are:

Application
Presentation
Session
Transport
Network
Data-Link
Physical