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Redundancy options when using stackwise-virtual

patoberli
VIP Advisor VIP Advisor
VIP Advisor

Hello

We currently have a more or less classic Cisco collapsed backbone with a central router (core) which has several distribution and datacenter switches attached to it (not shown in the drawing). We have now two additional external offices, with their own respective network. 

Our core is based on two C9500-24y4c routers, working together in stackwise-virtual (swv).

Our ISP is providing us with two separate uplinks to their MPLS network. Through this we can privately reach the other two locations. Currently we have setup static routing, but this has the downside, that I don't have real redundancy on our core. Problem is, the MPLS doesn't support spanning-tree, so I can't do a port-channel to the "cloud". Currently I have solved this with an ugly event manager applet, which checks the local syslog if the port on the primary C9500 goes down and then changes the interface IP address of the backup port and brings it up.

 

Do you have an idea how I could solve this more elegantly? The other locations have (old) Nexus as their routers in use, so OSPF should be possible, but I don't think BGP is licensed. What I'd like to achieve is to have both links UP/UP and a dynamic switching if the primary link fails. 

 

1 Accepted Solution

Accepted Solutions

Giuseppe Larosa
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

Hello @patoberli ,

what you can do depends on the type of service you get from the MPLS service provider.

It is an MPLS L2 service like a VPLS or it is an L3 service like an MPLS L3 VPN ?

 

>> Problem is, the MPLS doesn't support spanning-tree, so I can't do a port-channel to the "cloud".

It is not a question of Spanning Tree, if the two links are terminated on two different PE nodes a port-channel would be supported only if the two devices could pretend to be a single entity to create a multi chassis LAG Link Aggregation bundle like your SVL pair.

 

If the service is L3 VPN each device the SVL pair in HQ and the two remote sites have to peer / speak with the directly attached PE node so you could even use eBGP at HQ and OSPF at the remote sites but in any case you would need to work with the SP stuff to achieve the desired results.

 

If the service is L2 a possible option is to use OSPF combined with Flex links so that the secondary uplink is used only when the primary fails. On HQ SVL the IP address would be on an SVI interface interface VLAN.

In this case your devices would speak OSPF directly between each other with no SP devices in the middle.

 

Hope to help

Giuseppe

 

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2 Replies 2

Giuseppe Larosa
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

Hello @patoberli ,

what you can do depends on the type of service you get from the MPLS service provider.

It is an MPLS L2 service like a VPLS or it is an L3 service like an MPLS L3 VPN ?

 

>> Problem is, the MPLS doesn't support spanning-tree, so I can't do a port-channel to the "cloud".

It is not a question of Spanning Tree, if the two links are terminated on two different PE nodes a port-channel would be supported only if the two devices could pretend to be a single entity to create a multi chassis LAG Link Aggregation bundle like your SVL pair.

 

If the service is L3 VPN each device the SVL pair in HQ and the two remote sites have to peer / speak with the directly attached PE node so you could even use eBGP at HQ and OSPF at the remote sites but in any case you would need to work with the SP stuff to achieve the desired results.

 

If the service is L2 a possible option is to use OSPF combined with Flex links so that the secondary uplink is used only when the primary fails. On HQ SVL the IP address would be on an SVI interface interface VLAN.

In this case your devices would speak OSPF directly between each other with no SP devices in the middle.

 

Hope to help

Giuseppe

 

Thanks, it's what I expected. I think we will go another way for this now, probably with new Nexus and VPC and then run HSRP over it, or alternatively BGP if the license allows. 

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