Configuration Question

[matthew.scala]

I just need an explanation of the following to fully understand how this configuration works.. I'm guessing it's dealing with HSRP for fail-over of Layer 3 capabilities.. but I'm not sure.. if someone could explain this to me.. piece by piece, I would be most greatful. By the way.. we are running (2) core 6509 boxes (each with dual Sup1/MSFCs in them), trunked to each other.. and (2) access 6509 boxes, each with a trunk to each core (redundant.) So basically.. CORE1 has a trunk to each access box.. and CORE2 has a trunk to each access box. Here is an excerpt of the config on each core box.. (i changed the first 2 octets of the IP.. but i'm guessing that won't matter)

IP's:

187.2 - CORE2 - routerA

187.3 - CORE1 - routerA

187.4 - CORE2 - routerB

187.5 - CORE1 - routerB

*Note* - When I telnet to 187.1 address.. it brings me into CORE2 - routerA... why??

CORE1

interface Vlan108

description Management Subnet

ip address 150.19.187.2 255.255.255.224 alt ip address 150.19.187.4 255.255.255.224

no ip redirects

mls rp vtp-domain niprcaoc

mls rp management-interface

mls rp ip

standby 108 priority 100 preempt alt standby 108 priority 90 preempt

standby 108 authentication niprcaoc

standby 108 ip 150.19.187.1 alt standby 108 ip 150.19.187.1

CORE2

interface Vlan108

description Management Subnet

ip address 150.19.187.3 255.255.255.224 alt ip address 150.19.187.5 255.255.255.224

no ip redirects

mls rp vtp-domain niprcaoc

mls rp management-interface

mls rp ip

standby 108 priority 80 preempt alt standby 108 priority 70 preempt

standby 108 authentication niprcaoc

standby 108 ip 150.19.187.1 alt standby 108 ip 150.19.187.1

I know this is a lot to comprehend, but I'm confident someone will be able to explain this to me in a clear enough way, again, many thanks in advance.

[b.shoresh]

Hello Matthew.

First of all, you wrote that CORE2 Router A - 187.2, but from the configurations I can see that 187.2 is in CORE1 !!! So, when you telnet to 187.1 you are getting into 187.2(core1), which has a higher HSRP priority that 187.3(core2). 187.2 has HSRP priority of 100, 187.3 has HSRP priority of 80 - both of them share the same virtual-IP of 187.1, but as long as both of them up - the 6500 interface vlan 108 with the higher priority will respond.

Use the command " show standby brief" on both 6500s, and you will be able to see for each HSRP group, which router is the master and which router is the standby router.

Boaz.

[matthew.scala]

CORRECTION TO CONFIGURATIONS...

CORE1

interface Vlan108

description Management Subnet

ip address 150.19.187.3 255.255.255.224 alt ip address 150.19.187.5 255.255.255.224

no ip redirects

mls rp vtp-domain niprcaoc

mls rp management-interface

mls rp ip

standby 108 priority 80 preempt alt standby 108 priority 70 preempt

standby 108 authentication niprcaoc

standby 108 ip 150.19.187.1 alt standby 108 ip 150.19.187.1

CORE2

interface Vlan108

description Management Subnet

ip address 150.19.187.2 255.255.255.224 alt ip address 150.19.187.4 255.255.255.224

no ip redirects

mls rp vtp-domain niprcaoc

mls rp management-interface

mls rp ip

standby 108 priority 100 preempt alt standby 108 priority 90 preempt

standby 108 authentication niprcaoc

standby 108 ip 150.19.187.1 alt standby 108 ip 150.19.187.1

Sorry about the mix-up.. thanks again.

[7rbowenii]

Matt,

If the question is the same with the new config, then the reason .1 is active on Core2 is because it has a highest priority. Maybe I misunderstood the question.

-Bo