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Thursday, August 19, 2010

Will the HQ and remote office still be able to form EIGRP neighbor?

If we create a VRF on a switch (to provide traffic seperation on a remote site switch) and place an SVI in that VRF but do not enable MP-BGP, is there a VRF tag applied to traffic on that vlan? Therefore, if we have trunk connection to my SP (Layer2 VPN) that carries the VLAN that my SVI belongs to, will my HQ site that connects to the same VLAN, need to be VRF aware? Or can we still be able to establish an EIGRP peering between remote sites?

To summarize:

HQ and remote site have EIGRP peering established, over VLAN10. The vlan is extended end to end via the SP L2 VPN. Both HQ and remote office switches are currently using global routing table. We want to create a new VRF at remote site and place the SVI for theVLAN that connects to the HQ in that VRF. Will the HQ and remote office still be able to form EIGRP neighbor?

  • If you configure VRF in remote site but not in HQ the you will not able to communicate with HQ .
  • VRF is virtual routing table . If you configured any SVI interface to vrf then that interface or that network will not show in global routing table.
  • You can see that interface & route in VRF table. [ show ip route vrf (name) ].
  • vrf will create a instance of routing table.So if you configure vrf in remote location then you should have vrf in HQ to communicate.
  • MP-BGP is used in ISP cloud to send an VPNv4 update to remote PE . In customer network it won't require .
Please click here for further reference. Also for more information click here

  • Assuming your ISP allowing trunk between your sites. You have to configure address-family in your existing EIGRP process to allow the VRF to form the neighbor.
  • Here is the example and the link:

Router(config)# router eigrp 1

Router(config-router)# address-family ipv4 vrf RED

Router(config-router-af)# autonomous-system 101

Router(config-router-af)# network

Router(config-router-af)# default-metric 10000 100 255 1 1500

Router(config-router-af)# exit-address-family

Please click here for the reference guide.

Below are the fundamentals of VRF:

1) VRF creates a "virtual router" which is separate than your "native router."

2) You must specify which interfaces are attached to your "virtual router" under interface configuration mode (or else you will have no interfaces on that router).

3) Creating a VRF instance configures the router to stamp it's routing updates with a route descriptor, this stamp is used to inform other routers which "virtual-router" these updates are for.

4) Configuring VRF will not segregate data traffic. In order to segregate data traffic over the same link between the two routers on each side (the native and the virtual router) you would need to implement dot1q tagging and/or another layer 2 tagging technology like DLCI's or ATM PVC's. It seems that your provider is allowing QinQ tunneling so you can probably create a sub interface on the HQ and remote router and place the sub interface (dot1q) into the VRF.

Citation - This blog post does not reflect original content from the author. Rather it summarizes content that are relevant to the topic from different sources in the web. The sources might include any online discussion boards, forums, websites and others.

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