P2P wan link should be connected on ASR router or nexus switch

[Manindersinghnegi]

We need to establish a P2P link between 2 DC and I am wondering  what are pros and con of connecting P2P link on either router or Switch and what is the best practice.

Can someone please advice?

[Joseph W. Doherty]

The classic choice is between "intelligence" (router) and throughput (switch).

If the link is likely to be congested, enough that it's adverse to the apps, a router is often the better choice.

If congestion won't be an issue, a switch usually is able to push more bits for the same or lower cost.

Unfortunately, the demarcation between routers and (L3) switches continues to blur as router have been incorporating more and more switch like hardware to enhance their performance, while switch hardware continues to get smarter and smarter.

[Giuseppe Larosa]

Hello @Manindersinghnegi ,

>> We need to establish a P2P link between 2 DC and I am wondering what are pros and con of connecting P2P link on either router or Switch and what is the best practice.

What kind of DC interconnect service you would like to use ?

if you want a L2 extension of a subset of VLANs without any control on BUM traffic levels ( Broadcast Unknown Unicast Multicast) you can use a simple 802.1Q trunk between switches.

if you want to implement a more advanced L2 transport service there are several options that can work:

a)  old basic EoMPLS combined with policers on input interfaces for BUM traffic

b)  L2tPv3 p2p service VLAN based combined with policers on input interfaces for BUM traffic

c)  VPLS LDP based  combined with policers for BUM traffic

d) OTV if you are using ASR 1000 and you have the appropriate licenses. It is now considered old but it works.

e) more modern one can be MP BGP L2VPN EVPN with VXLAN encapuslation this one minimizes  BUM at the control plane level. This can be supported both on ASR 1000 or Catalyst 9000 or Nexus 9000 series with appropriate licenses

Other options are possible like using a GRE tunnel.

The well established for p2p are L2TPv3.

VPLS or BGP EVPN or OTV can support multi homing ( when you will add a second link between the same two DCs)

Hope to help

Giuseppe

[Manindersinghnegi]

A simple P2P link with BGP running over it.

[balaji.bandi]

Its all depends on requirement i prefer to have router (does the router able to handle that kind of traffic you looking )

Switch - big security risk

[Manindersinghnegi]

load sharing is main concern, we want traffic from DC1 (SW)----BGP---DC2(SW)-  to land at Switch at DC2 and form switch we can load share traffic to DC2 WAN1 or WAN 2.

DC1 (SW)----BGP---DC2(SW)---WAN1 or WAN2 

[balaji.bandi]

What kind of Link is this VPLS? MPLS? Dark Fibre?

As security concerns are addressed, you okay with terminating at SW. ( may be try some MACsec or VRF or VRF).

[Manindersinghnegi]

VPLS

[balaji.bandi]

VPLS is ok to terminate at switch -(make sure that is isolated different VLAN or VRF )  DC1 and DC2, and use WAN1 and WAN2 links

[Joseph W. Doherty]

"load sharing is main concern. . ."

For basic load sharing (ECMP), both would work the same.  For load balancing, if supported, only routers used to do (PfR) but unsure that's still true.  Possibly, some switches DLB might even be as good for basic LB.