Dynamic Routing over vPC possible in 7.2 NX-OS ?

[ahmad82pkn]

Hi, As per Nexus Release 7.2 , now dynamic routing is supported over Nexus that may over come Design 3 Problem.

but i am not getting any example configuration for this, Also there is confusing pre req for this, can someone help explaining ? or may be some good example config?

http://bradhedlund.com/2010/12/16/routing-over-nexus-7000-vpc-peer-link-yes-and-no/

7.2 Release for Nexus states.

Dynamic Routing over vPC

Dynamic Routing over vPC feature enables L3 routing protocols such as OPSF to form adjacency with the two vPC peer chassis. The equal routing cost matrices must be configured on applicable interface on each of the vPC peers, failure to do so can result in blocking the traffic. Asymmetric routing feature has to be implemented to address this issue and to configure Dynamic Routing over vPC. Additionally, when Dynamic Routing over vPC is enabled a warning log message is printed.

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/7_x/nx-os/release/notes/72_nx-os_release_note.html

[Ashutosh Chauhan]

I have referred few new documents from ciscowhich are saying now it is possible to set up peer adjacency between Layer 3 device and vPC peer without separate Layer 3 links. Is it really the case or still we are having few limitations? I hope we don't have a note which says it is mandatory to use Saperate Layer 3 link for Layer 3 adjacency between layer 3 devices with VPC peer.

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/nx-os/interfaces/configuration/guide/b-Cisco-Nexus-7000-Series-NX-OS-Interfaces-Configuration-Guide-Book/configuring-vpcs.html#task_E034B3298DC945D1A33AB27AF73AE88C

[alessandro.dona]

Hi Guys,

for me is not clear if also peer link should use F2E or F3 or it is mandatory use F2E or F3 only for the vPC to whic my router is attached?

[m1xed0s]

Not intend to hi-jack the post but is your topology similar to mine? I use EIGRP instead of OSPF though.

https://supportforums.cisco.com/discussion/13168356/updatedlayer-3-routing-over-vpc-peer-link-n9k-lastest-72-code

[Muhammed Madappalli]

please clarify the Routing over vPC support on Pre and Post 7.X nx-os on Nexus 7000

vPC Over routing issue Pre 7.x setup (nexus 7000):

confused whether the issue was not be able to form ospf neighbourship between an Layer-3 device and vPC peers (both) or the issue was with routed traffic routed to vPC peer over the peer link will not be forwarde to another link?

Dynamic routing protocol uses multicast hello messages in most cases and multicast traffic recieved on vPC member port will always will be forwarded across the peer-link? then what was stopping it from peering across peer-link? why the TTL is becoming an issue for a Layer-2 switched traffic?

let's asume we can peer each other, then why the peer-gateway feature will not stop the traffic from crosing peer-link in pre 7.x NX-OS?

Post 7.x:

it is required to enable peer-gateway feature and routing metric should be same. so does the layer-3 vPC routing solves the TTL Issue or unpredictable Traffic forwarding behaviour in pre 7.x deployment?

[ajc]

Hi Steve, are Brad examples from 2010 still valid? .Based on your note from 2015 to the following link:

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/nx-os/interfaces/configuration/guide/b-Cisco-Nexus-7000-Series-NX-OS-Interfaces-Configuration-Guide-Book/configuring-vpcs.html#concept_F862A25175DE4C738065F0EDA6F5D8C0

has changed, the references to your note from 2015 are now different. After reading Brad Blog, the examples, I assume for Diagram # 3 the blue individual links to each FW are VPC PORT Members and that's why it does not work (loop avoidance takes place). 

http://bradhedlund.com/2010/12/16/routing-over-nexus-7000-vpc-peer-link-yes-and-no/

I am also not clear how the Peer Gateway works when Brad said it does not help on Diagram # 2. Any explanation you could kindly provide on this topic? How the traffic flows when the Peer Gateway is used? 

thanks