HSRP Tracking

In previous blog we have seen if our primary router goes down backup router will provide redundancy. But there is some other possibility also.

Here R1 and R2 are client side router connected to R3 (ISP) router. R1 working as a Primary and R2 working as a secondary. Now what if "S1/1" of R3 goes down and still we don't have any configuration for this. So according to our previous configuration R1 still act like Primary. So with help of HSRP we can track our interfaces also.
Configuration-

R1(config)#int s 1/1
R1(config-if)#ip address 192.168.3.1 255.255.255.0

R1(config)#int f0/0
R1(config-if)#ip add 192.168.1.2 255.255.255.0
R1(config-if)#standby 1 ip add 192.168.1.1      //Virtual ip
R1(config-if)#standby 1 priority 105           // Making Primary
R1(config-if)#standby 1 preempt
R1(config-if)#standby 1 track serial 1/1


and on R2-
R2(config)#int s 1/0
R1(config-if)#ip address 192.168.2.1 255.255.255.0

R1(config)#int f0/1
R1(config-if)#ip add 192.168.1.3 255.255.255.0
R1(config-if)#standby 1 ip add 192.168.1.1      //Virtual ip
R1(config-if)#standby 1 priority 100           //Making Secondary
R1(config-if)#standby 1 preempt
R1(config-if)#standby 1 track serial 1/0


Now go on R3 and shutdown S1/1. You'll R2 will become Primary.

Simple Redistribution Scenario

This task is very simple so do it. Only thing which may confuse some one why we are creating loopback interface as point-to-point. Then answer is by default OSPF doesn't take loopback as a real interface so if you are not creating it as point-to-point then it'll show the interface with /32 mask.So go in each and every loopback and do it as-

R2(config)#interface loopback 1
R2(config-if)#ip address 10.1.7.1 255.255.255.0
R2(config-if)#ip ospf point-to-point

* When we are redistributing routes in EIGRP and RIP we have to give metric value because by default both protocols take infinite metric.

* When we are redistributing is OSPF by default metric (seed metric) is 20. So if we are doing redistribution no need to provide metric until it doesn't ask. :P

* When we are redistributing is OSPF there are 2 option to set metric E1 and E2. By default it is E2 which means metric will not increase in network. We use it when there is only one way to go out. If we have multiple way then we'll use E1 which means metric is incremental in network. And now OSPF will decide which is better way.

* By default OSPF summarize redistributed network so we'll use 'subnet' when redistributing.

R2(config)#router ospf 1

R2(config-router)#redistribute eigrp 100 subnet

"Now check the metric type and metric on R3"

R2(config)#router eigrp 100
R(config-router)#redistribute ospf 1 metric 100 100 100 100 100

"Metric of EIGRP is little bit complex Bandwidth, Load, Delay, Reliability,MTU. So for now I am providing random values"


   

Here we need to filter routes. And here I am doing filtering using ACL.

Create ACL that permit odd numbered loopbacks.

R2(config)#access-list 1 permit 10.1.1.0 0.0.0.255
R2(config)#access-list 1 permit 10.1.3.0 0.0.0.255
R2(config)#access-list 1 permit 10.1.5.0 0.0.0.255
And apply it on OSPF.

R2(config)#router ospf 1 

R2(config-router)#distribute-list 1 out
"Now look at routing table of R3"







Here we can also use ACL but we have one another better way to doing this that is by using prefix list.

First create a prefix-list-

R2(config)#ip prefix-list CCNP permit 10.0.0.0/8 le 24

"Now this prefix list allow only network 10.0.0.0 which have mask between 8-24"


Now we need to create route-map-

R2(config)#route-map FILTER_OSPF_TO_EIGRP //It's only route map name

R2(config-route-map)#match ip address prefix-list CCNP

"Rote map work like if-else statement in programming. Here we use Match-set statement. But by default if we are not providing any no and set statement then it start from 10 and permit"

Now apply this may in redistribution-

R2(config)#router eigrp 100
R2(config-router)#redistribute ospf 1 metric 100 100 100 100 100 route-map  FILTER_OSPF_TO_EIGRP

All objective are done. If still you have any doubt and write your question in comment box or join our group for discussion on any point. Link of group is give in left side of page.

Thanks. Have a good day.

Implementing Basic EIGRP

Setup a lab in GNS as given in diagram. 

Configure all loopbacks on BB Router and also configure all the interface of BB, R2 and R3.

Now -

BB(config)#router eigrp 90

BB(config-router)#network 172.30.0.0 0.0.255.255

BB(config-router)#network 10.1.0.0 0.0.255.255

BB(config-router)#no auto-summary  //("By default RIP and EIGRP supports auto summary.")

R2(config)#router eigrp 90

R2(config-router)#no auto-summary
R2(config-router)#network 10.1.2.2 0.0.0.0
R2(config-router)#network 10.1.24.2 0.0.0.0
R2(config-router)#network 10.1.25.2 0.0.0.0 //("It is mentioned that use specific wild card mask")

R3(config)#router eigrp 90
R3(config-router)#no auto-summary
R3(config-router)#network 10.1.2.1 0.0.0.0
R3(config-router)#network 10.1.34.2 0.0.0.0

Now we need to create static route on BB.

BB(config)#ip route 192.168.1.0 255.255.255.0 null0
and

BB(config-router)#network 192.168.1.0

Now look at tables-
"show ip route"

"show ip eigrp neighbor"

"show ip eigrp topology"

BB(config)#ip default-network 192.168.1.0

No look at routing table of R3 and R3.

D*   192.168.1.0/24 [90/20512000] via 10.1.24.1, 00:00:14, Serial1/0

"* denotes default route pointing to network".
.





Make passive interface where EIGRP doesn't exist.

BB(config-router)#passive-interface default      //"making all interface passive"
BB(config-router)#no passive-interface serial 0/0     //"Making active interface"
BB(config-router)#no passive-interface serial 0/1    //"Making active interface"

"EIGRP" have befit over OSPF we can summarize network at any point but in OSPF we can summarize on border routers only.

BB(config-if)#ip summary-address eigrp 90 172.30.0.0 255.255.248.0   //"on both serial interface"


"After doing this on one interface look at routing table on both router and have a look on next hop on routes"







 
EIGRP is the only routing protocol which supports unequal load balancing.

BB(config-router)#variance 2


Now have a look on tables. And still have any doubt type in comment box.