Interface tracking & IP SLA

[ganeshdhungana]

Hi Mentors,

I have a dual connection from two service providers ( provider A & Provider B).

In my internal network,  I have two Vlans (vlan10 & vlan 20).

My requirement is users belonging to vlan10 should go via ISP A and for vlan 20, it should go via ISP B.

So, for that purpose, I configured HSRP along with intervlan routing and that worked quite fine.

I have two Cisco AS5300 routing connecting to both ISPs and they are terminated to a common switch Cisco2950.

All are in ethernet technology, serial technology has not been used.

# "IP SLA" command is not supported in CiscoAS5300.

I configured the interface tracking command for HSRP as well.

But,

Where the problem lies is...

When one link goes down then it doesn't fail over and go through another link. To fail over, I should manually remove

the external link connecting to the router. And another thing is, if i pulled the cable connecting to the internal network then

it fails over.

# "IP SLA" command is not supported in CiscoAS5300.

###The summary is: I am trying to implement a failover using HSRP in Cisco AS5300 but the interface tracking is not

decresing the priority value when the connection is lost with the ISP and IP SLA is also not supported. So, in this case what can i do to make

a perfect failover for the network ??

Regards,

Ganesh Dhungana

[Calin C.]

Hello

According to the Cisco Feature Navigator AS5300 supports IP SLA ICMP Echo operation. What software version do you have?

Second, with IP SLA + tracking you'll achieve redundancy, but you need PBR for the routing part if you want to split the users over multiple providers.

I did write some tutorials a while ago, for IP SLA and PBR. I will list them below maybe you'll find something useful:

http://www.firstdigest.com/2010/05/cisco-policy-routing-with-ip-sla/

http://www.firstdigest.com/2010/05/cisco-ip-policy-routing-with-ip-sla-and-eem/

http://www.firstdigest.com/2008/12/cisco-traffic-manipulation-with-policy-based-routing/

Nevertheless, first you need to really check for IP SLA support.

HTH,

Calin

[Rajesh Hirani]

Can you share your configration with us?

[ganeshdhungana]

Hey Calin,

Thank you very much for the reply as i had not got any it since I posted the particular disscussion.

The IOS that I am using in my Cisco AS5300 is c5300-ik9s-mz.123-22.bin. I went to the feature nagivator from the cisco.com website and its showing that the IOS supports IP SLA feature. But when I go the global configuration mode and

try to type IP SLA then I get an error. So, I am pretty puzzled.

Apart from this,

I want to set redundancy in my network as I have using dual ISPs at a same time for different VLANs.

Will PBR using route map would do for me ?? Or is there any other solution for the failover?

Note: I am having fibre connection from both the ISP so it has been terminated as FastEthernet link. So, serial connection is there.

Hoping for the reply very soon.

Regards,

Ganesh Dhunagna

[Calin C.]

For the redundancy part PBR will work fine, but I need to know how to you have setup the LAN gateways on the router. You have one physical interface with subinterfaces, like .10 and .20 for each VLAN subnet, and the interface is connected to a switch?

At the simple part, PBR will work like:

- one ACL or Prefix-list to match vlan 10 subnet

- one ACL or Prefix-list to match vlan 20 subnet

- one route-map for VLAN 10, to be applied on the .10 subinterface (if what I assume is correct)

route-map VLAN10 permit 10

  match ACL (Prefix-list) for vlan 10

  set next-hop Provider A

route-map VLAN10 permit 20

  match ACL (Prefix-list) for vlan 10

  set next-hop Provider B

route-map VLAN10 permit 100

- one route-map for VLAN 20, to be applied on the .20 subinterface

route-map VLAN20 permit 10

match ACL (Prefix-list) for vlan 20

set next-hop Provider B

route-map VLAN20 permit 20

match ACL (Prefix-list) for vlan 20

set next-hop Provider A

route-map VLAN20 permit 100

This will do policy routing and will implement a certain level of redundancy. You will not be able to change the route dinamically without IP SLA + tracking, but still you will have some safety net in case the primary line for each subnet goes down.

If you don't understand something please let me know and I will try to help more.

HTH,

Calin