Note: This is a dump from my notes of the day, I will write more posts on each subject for my training in the future and elaborate as I go on.
Just a quick late night post. Due to the changing of the CCNP exams from 31st January, its spurred me on to do something Exam wise, I’m self studying the CCNA Security, but after finding a cheap last-minute deal with the Knowledge Academy, I’ve booked myself on a 10 day CCNP course.
I don’t expect to be able to pass the exam’s at the end of the course, after all its essentially 3 Cisco Press books, once per exam (SWITCH, ROUTE, TSHOOT). And some training vendors offer this course for 15 days +. Therefore I expect to be catapulted into the CCNP curriculum allowing me to continue my deeper studies further and pass the exam.
Just before I booked this course, I also bought Chris Byrant’s video course on udemy.com (gave me free CCNA Security Videos too!), I’ve not watched the videos for the CCNP yet, but for the CCNA Security the website seems buggy!
What I learnt today – Start on CCNP Route
So as usual, the first day is ice breakers, discovering what level you’re at and where other people are on the ladder.
We have dived into ROUTE first and then will hit SWITCH later on in the course. The idea being that TSHOOT topics will be covered throughout as we go on.
It became clear quickly that my ability to work out subnets, with hosts etc has fallen into the deepest corners of the vaults of my mind, I will have to dig that out and fast.
EIGRP is the first thing up, and ironically one of the first things covered in the ROUTE book, no surprise there, makes it nice and easy to follow if doing some homework in the night-time. So let me dump down my notes
Hybrid protocol (Distance Vector if your picky)
1. equal load balancing
2. unequal load balancing – using the variance parameter (Variance=1)
3. Classless Variable subnetting
4. Sends updates using multicast on 126.96.36.199
5. Handles authentication using a keychain and therefore multiple keys which can be given lifetimes.
The routes provided are classed as
- Best route
- installed into the route table
- appears in the eigrp topology table
Reported/ Advertised Distance
- Feasible successor
- 2nd best route
- NOT installed into the route table
- appears in the eigrp topology table
“Show ip eigrp topology all” = show all routes in the topology table
Routes are decided by DUAL = Diffusing Update Algorithm
Which is made up of 5 K values, two values are used in the algorithm, the others are ignored
- K1 – Bandwidth – 1
- K2 – Load – 0
- K3 – Delay – 1
- K4 – Reliability – 0
- K5 – MTU – 0
The 0 and 1 represent which of the values are “turned on” i.e used. By default it is Bandwidth and Delay.
The Calucation = [K1 x bandwidth + (K2 x Bandwidth / 256 – Loa) + K3 x Delay ] x [K5 / (Reliability + K4)]
When using the default values to be used, this can be summarised to;
256 x (10 power 7 / least bandwidth of a link + Total delay of all links)
Notice that the MTU value is not used in this calculation at all (K5 is which will be either 0 or 1)
EIGRP Packet Types;
- Hello (keepalives)
- Updates (Triggered, incremental)
- Query (SIA Queries)
- Reply (SIA Replies)
- Acknowledge (Ack of updates, queries + replies)
2 – 5 are sent by RTP (Reliable Transport Protocol)
Hello is there somebody in there?
Hello timers, are there to make things work.
On a line that is below T1 (Less than 1.544 Mbps)
Hello Timer sent every 60 Seconds, this is x3 for the Dead timer = 180 Seconds
On a Line that is above T1 (More than 1.544 Mbps)
Hello Timer sent every 5 Seconds, this si x 3 for Dead timer = 15 Seconds.
Query timers “live” for 3 minutes. After 1 and half minutes, an SIA Query is sent (Stuck in Active)
When the timer hits 0 the neighbor relationship is destroyed.
Hello packets are used to re-establish any links.
To reduce SIA queries in the network, it is recommended to use summary routes.
For all routers in a “domain” to form a relationship, they must have the same Autonomous System Number (ASN) which can be from 1 – 65,535.
1. Check K values match on both sides of the router link
2. ASN configuration must match on routers
3. Authentication must match (if used on any routers)
4. Advertise the common subnet on both routers i.e the link between the routers
5. No passive interface is set on common interface i.e the link between routers.
Commands to use to verify the configuration of EIGRP
- show ip eigrp interfaces – lists interfaces on which EIGRP is enabled (omits passive interfaces)
- show ip protocols – Lists contents of the network configuration for each routing process
- show ip eigrp neighbors – Lists EIGRP neighbors that are known, if parameters mismatch between routers, they will not show as neighbors in this output
- show ip eigrp topology – Lists all successor and feasible successor routes known to the router
- show ip route – shows contents of routing table, route learnt via EIGRP are marked with a D
Below is a Visio of the topology we used for the day. After establishing EIGRP routes, we changed the bandwidth and delay to look at the changes in the route and what appears in the router table.
- Configure each router with the serial interfaces and ip addresses, ensure you can ping from one router to another.
- Configure routing protocol in global configuration mode;
- router eigrp [ASN}
- network [subnet] [wildcard]
Ciao for now, Dean