Solved: Re:HA between routers 2911

mateomateo1 · ‎03-27-2013

Hi,

I have to build HA environment, at the moment we have only one R1 and WAN1 but company wants to buy R2 + WAN2 and have HA between the routers, in case R1 or WAN1 goes down the other router will take over.

What would be standard methodology nowadays to do that - does HSRP will do what I need or it is better do some other way? can anyone point me in the right direction.

Kimberly Adams · ‎03-27-2013

Matt,

Here is some of the information for this:

Network Diagram

This document uses the network setup shown here:

In this diagram, Router 1 (R1) and Router 2 (R2) are in AS 100, which has external BGP (eBGP) peering with ISP-A (AS 300) and ISP-B (AS 400) respectively. Router 6 (R6) is a part of AS 600, which has eBGP peering with ISP-A and ISP-B. R1. R2 has iBGP peering, which is necessary to ensure optimal routing. For example, when you try to reach AS 400 internal routes, R1 does not employ the longer path over AS 300. R1 forwards the traffic to R2 instead.

R1 and R2 are also configured for HSRP over a common Ethernet segment. Hosts on the same Ethernet segment have a default route that points towards the HSRP standby IP address 192.168.21.10.

Configurations

R1

Current configuration

hostname R1
!
interface serial 0
ip address 192.168.31.1 255.255.255.0
!
interface Ethernet1
  ip address 192.168.21.1 255.255.255.0
  standby 1 priority 105
  standby 1 preempt delay minimum 60
  standby 1 ip 192.168.21.10
  standby 1 track Serial0

!--- The 
standby track serial command tracks the state of 
!--- the Serial0 interface and brings down the  
!--- priority of standby group 1, if the interface goes down.
!--- The 
standby preempt delay minimum 60 command makes sure that 
!--- R1 preempts and takes over as active router again. This command also ensures that
!--- the router waits 60 seconds before doing so in order to give BGP time enough
!--- to converge and populate the routing table. This avoids
!--- traffic being sent to R1 before it is ready to forward it.

!
!
router bgp 100
  no synchronization
  network 192.168.21.0
  neighbor 192.168.21.2 remote-as 100
  neighbor 192.168.21.2 next-hop-self
  neighbor 192.168.31.3 remote-as 300
  no auto-summary
!

R2

Current configuration:  

hostname  R2 
!
interface serial 0  
ip address 192.168.42.2 255.255.255.0  
!
interface Ethernet1  
 ip address 192.168.21.2 255.255.255.0  
 standby 1 priority 100  
 standby 1 preempt  
 standby 1 ip 192.168.21.10  
! 
!  
router bgp 100  
 no synchronization  
 network 192.168.21.0   
 neighbor 192.168.21.1 remote-as 100  
 neighbor 192.168.21.1 next-hop-self  
 neighbor 192.168.42.4 remote-as 400  
 neighbor 192.168.42.4 route-map foo out 

!--- It appends AS 100 to the BGP updates sent to AS 400 
!--- in order to make it a backup for the ISP-A to R1 path.

 no auto-summary  
!  
access-list 1 permit 192.168.21.0  
route-map foo permit 10  
 match ip address 1  
 set as-path prepend 100  

end

Verify

This section provides information you can use to confirm your configuration is working properly.

Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output.

When you configure redundancy in any network, you must consider two things:

The creation of a redundant path for packets going from a local network to a destination network.
The creation of a redundant path for packets coming back from a destination to a local network.

This information was from the link I gave you.

Thanks and Cheers!

Kimberly

Please remember to rate helpful posts.

Thanks and Cheers! Kimberly Please remember to rate helpful posts.

View solution in original post

Kimberly Adams · ‎03-27-2013

Matt,

Yes HSRP would be the best way to have HA and failover to the R2 and WAN2. You would need to configure your HSRP to track your WAN1 and failover to R2 and WAN2 if WAN1 link goes down. If you need some configuration assistance let me know.

Thanks and Cheers!

Kimberly

Please remember to rate helpful posts.

Thanks and Cheers! Kimberly Please remember to rate helpful posts.

mateomateo1 · ‎03-27-2013

Thank you for quick reply, if you dont mind Kimberly I would appreciate for link or example on how to do this.

Sent from Cisco Technical Support iPhone App

Kimberly Adams · ‎03-27-2013

Matt,

Here is a link for the basics of configuring HSRP:

http://www.cisco.com/en/US/customer/tech/tk365/technologies_configuration_example09186a0080093f2c.shtml

This link shows how to do this with BGP, but the basics of HSRP are there with some configuration examples and diagrams. Be sure to track the serial interface, so when it goes down it will failover to the R2 with WAN2.

Thanks and Cheers!

Kimberly

Please remember to rate helpful posts.

Thanks and Cheers! Kimberly Please remember to rate helpful posts.

Joseph W. Doherty · ‎03-27-2013

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Yes, HSRP might be used. GLBP too, if you want to try better gateway load balancing.

However, since your diagram shows a dual 3750 stack, and since 3750s can route, I would suggest putting the LAN gateway(s) on the stack and routing between the L3 enabled 3750 stack and your WAN routers. You also might want to MEC between the 2911s and your stack (good if you can do same for your edge 2960s too).

mateomateo1 · ‎03-27-2013

I cant access that website , it says i do not have permissions ... could you post some other link please

Sent from Cisco Technical Support Android App

Kimberly Adams · ‎03-27-2013

Matt,

Here is some of the information for this:

Network Diagram

This document uses the network setup shown here:

In this diagram, Router 1 (R1) and Router 2 (R2) are in AS 100, which has external BGP (eBGP) peering with ISP-A (AS 300) and ISP-B (AS 400) respectively. Router 6 (R6) is a part of AS 600, which has eBGP peering with ISP-A and ISP-B. R1. R2 has iBGP peering, which is necessary to ensure optimal routing. For example, when you try to reach AS 400 internal routes, R1 does not employ the longer path over AS 300. R1 forwards the traffic to R2 instead.

R1 and R2 are also configured for HSRP over a common Ethernet segment. Hosts on the same Ethernet segment have a default route that points towards the HSRP standby IP address 192.168.21.10.

Configurations

R1

Current configuration

hostname R1
!
interface serial 0
ip address 192.168.31.1 255.255.255.0
!
interface Ethernet1
  ip address 192.168.21.1 255.255.255.0
  standby 1 priority 105
  standby 1 preempt delay minimum 60
  standby 1 ip 192.168.21.10
  standby 1 track Serial0

!--- The 
standby track serial command tracks the state of 
!--- the Serial0 interface and brings down the  
!--- priority of standby group 1, if the interface goes down.
!--- The 
standby preempt delay minimum 60 command makes sure that 
!--- R1 preempts and takes over as active router again. This command also ensures that
!--- the router waits 60 seconds before doing so in order to give BGP time enough
!--- to converge and populate the routing table. This avoids
!--- traffic being sent to R1 before it is ready to forward it.

!
!
router bgp 100
  no synchronization
  network 192.168.21.0
  neighbor 192.168.21.2 remote-as 100
  neighbor 192.168.21.2 next-hop-self
  neighbor 192.168.31.3 remote-as 300
  no auto-summary
!

R2

Current configuration:  

hostname  R2 
!
interface serial 0  
ip address 192.168.42.2 255.255.255.0  
!
interface Ethernet1  
 ip address 192.168.21.2 255.255.255.0  
 standby 1 priority 100  
 standby 1 preempt  
 standby 1 ip 192.168.21.10  
! 
!  
router bgp 100  
 no synchronization  
 network 192.168.21.0   
 neighbor 192.168.21.1 remote-as 100  
 neighbor 192.168.21.1 next-hop-self  
 neighbor 192.168.42.4 remote-as 400  
 neighbor 192.168.42.4 route-map foo out 

!--- It appends AS 100 to the BGP updates sent to AS 400 
!--- in order to make it a backup for the ISP-A to R1 path.

 no auto-summary  
!  
access-list 1 permit 192.168.21.0  
route-map foo permit 10  
 match ip address 1  
 set as-path prepend 100  

end

Verify

This section provides information you can use to confirm your configuration is working properly.

Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output.

When you configure redundancy in any network, you must consider two things:

The creation of a redundant path for packets going from a local network to a destination network.
The creation of a redundant path for packets coming back from a destination to a local network.

This information was from the link I gave you.

Thanks and Cheers!

Kimberly

Please remember to rate helpful posts.

Thanks and Cheers! Kimberly Please remember to rate helpful posts.

mateomateo1 · ‎04-03-2013

thank you, it worked great!

just have a question if i add extra 3750-x to my scenario will that need extra config for routers or switches? sothing like that:

could you also point me or recommend a book with different types of set-ups (for high availibility) on cisco devices please.