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Routing problem with MPLS/ISIS

CliveG
Level 1
Level 1

Hi,

We have a 3 x DC architecture that can be summarised as per below:

DC1 - West London
DC2 - Telehouse West
DC3 - Telehouse North
DC1 has an ethernet metro line directly to DC2 and DC3 and likewise DC2 and DC3 have a X-Connect within Telehouse, thus forming a tringle.

Originally all of our external traffic from West London (DC1) exited via Ethernet metro to Telehouse North.
To upgrade the connectivity and create DC redundancy, I organised better bandwidth uplinks from Telehouse West.
At DC2 and DC3 as well as transit connectivity we also have LINX Connectivity.
I now have traffic exiting our network via Telehouse West, thus allowing us to upgrade Telehouse North, or should be, except for one issue as explained below:

Traffic destined for the outside world is still traversing Telehouse North (DC3) first and then Telehouse West (DC2) instead of direct to Telehouse West.
Unfortunatly, I am on a network that cannot be "Down" for any reason (other than the obvious complete hardware failure etc).

The internal routing is being handled by ISIS/MPLS and given that I am not a Cisco expert (worked on Juniper mainly over the past several years), I was hoping someone may be able to aid in resolving how I can get the routing changed to go direct over the ethernet metro from DC1 to DC2 without going to DC3 first.

On top of that, I cannot make use of the upgraded LINX connectivity at DC2 because of the above issue. The BGP open packet wants to exit via DC3 and LINX Collector naturally sees this from the wrong address and drops the packets.

Here is the ISIS/MPLS configs I can see on DC1:

router isis 40000
vrf VFM
net 49.4000.4013.4013.00
metric-style wide
redistribute connected

router isis

router isis <ASN>
net 49.3323.9613.9613.00
metric-style wide
redistribute connected
redistribute static ip
maximum-paths 8
address-family ipv6
multi-topology
redistribute connected
redistribute static
exit-address-family

And DC3:

router isis <ASN>
net 49.3323.9612.9614.00
metric-style wide
metric 100
redistribute connected
redistribute static ip
maximum-paths 8
distance 100 clns
address-family ipv6
multi-topology
redistribute connected
redistribute static
exit-address-family

And DC2:

router isis 40000
vrf VFM
net 49.4000.4011.4011.00
metric-style wide
redistribute connected

router isis MULTICAST
net 31.3131.3131.3131.00
metric-style wide

router isis <ASN>
net 49.3323.9611.9611.00
metric-style wide
metric 100
redistribute connected
redistribute static ip
maximum-paths 8
distance 100 clns
address-family ipv6
multi-topology
redistribute connected
redistribute static
exit-address-family

If any other information is required then please let me know and I will supply.

Many thanks

29 Replies 29

Hi Harold,

My apologies. I neglected to mention that all three DCs are running the following:

DC1 - 2 x C6880-X in VSS - Port-Channel to DC2 and direct ethernet metro link to DC3
DC2 - 2 x C6880-X in VSS - Port-Channel to DC1 Ethernet Metro and X-Connect to DC3
DC3 - 2 x C6880-X in VSS - Direct connect to DC1 Ethernet Metro and X-Connect to DC2

I will get the output of the commands you have asked for in the morning.

Again, thank you