MY CCIE JOURNEY

Eigrp Authentication:

* 3 parts to remember while configuring Authentication

* key creation and management

* Authentication mode

* assigning key to an interface

* key chain should be configured first and this is done under global configuration mode

* Create key

* Create key string , send lifetime , accept lifetime

* Info configured can be seen by issuing the command SHOW KEY CHAIN

* Next step is to apply it to an interface

* ip authentication eigrp 1 mode md5 ---> this is the authentication mode

* all constructed elements should be relevant and also they must and should be case sensitive with key strings and authentication modes being equal

Default Information originate and How to avoid it :

* In order to suppress the default routes , we can go into the router config mode of eigrp and issue the command as follows

* ROUTER EIGRP 1 ---> NO DEFAULT-INFORMATION IN


CREATION OF DEFAULT ROTUE:

* If we want to have a default route , we have more than one way to do it

* If we have a static route configured , redistribute the static route with a some of the default metric value

* Another way is to use the summary address in the interface level config mode to accomplish this task

* INT FA0/0 ---> IP SUMMARY-ADDRESS 0.0.0.0 0.0.0.0


Eigrp Load Balancing:

* By default eigrp loadbalances across 4 equal cost paths

* We can change the number of paths any where between 0-6 with the issue of MAXIMUM PATH command in router config mode

* For unequal load balancing we can use the VARIANCE COMMAND which ranges from 0-128

* This is done under router config mode
VARIANCE X --->it load balances between the routes which are x times more than the best one

* This is cost based load balancing sharing 1:x(will be done based on the variance level ) ratio of packet traffic

* If we want to alter this , this can be done under router configuration mode

* ROUTER EIGRP 1 ---> TRAFFIC SHARE MIN

* In this way the minimum cost will be preffered

* If we want to revert back to normal behaviour it should be done again in the router config mode
ROUTER EIGRP 1 ----> TRAFFIC SHARE BALANCED ----> defaults will be applied

* As a side note route tagging can also be used to acheive this task

EIGRP TIMERS :

* Update timer : rate at which updates are being sent

* Invalid timer: the time interval after which a route is declared as invalid

* Hold timer: how long the route is holded on depending on the other routes received

* Flush timer: the time after which the route is removed from the routing table

* Hello timer: hello interval defines how often hello packets are sentout which are used to establish neighbouring relationships

* On t1 or faster interfaces the dafault value being 5 secs and on nbma or slower links the timer value being 60 seconds

* If we want to change the timers , it should be done both ends and also this behaviour also applies to bandwidth command

* SHOW IP PROTOCOLS can be used to check the values

* The change should be done across the interface level
IP HELLO-INTERVAL EIGRP 100 15 --> this sets the interval to 15

* The same confiuration can be done for the HOLD time changes

* By default the hold time will be 3 times more than the hello timer

* Changing one timer will not change the other timer

* ACTIVE TIMER : this is used to minimize the effect of STUCK IN ACTIVE problem

* THIS CAN BE DONE ---> ROUTER CONFIG MODE ---> ROUTER EIGRP 1 ---> TIMERS ACTIVE TIME 180

SPLIT HORIZON:

* May arise with secondary/multipoint situations

* can be closed down under interface level configuration mode

* INT FA0/0 ---> NO IP SPLIT HORIZON EIGRP 100 ---> this disable split horizon

* We can also use VALIDATE UPDATE SOURCE command mostly done with secondary address in place

* ROUTER EIGRP 1 ---> NO VALIDATE UPADTE SOURCE

* you may land up with an error in times "ROUTER NOT ON COMMON SUBNET"


EIGRP STUB ROUTING:

* CONFIGURATION IS DONE UNDER ROUTER MODE

* EIGRP STUB ---> can have different parameters

* receive-only , connected , static , summary all of them being obvious and the point is to redistribute



* also not all the config commands are from console line so of them may have hifuns (-) between them or not i just used them


regards
rakesh