CISSP New Book

There is a new 4th Edition CISSP book:

IP Precedence Values

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

Juniper Certifications

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

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

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

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

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.