L3 Port-channel vs individual L3 links (equal cost load balancing)

[LynK]

Sup guys!

I got a fun question for ya. Lets say you are running layer 3 down to you access switches. Would you do L3 port-channels or L3 links using ECLB? Tell me what you would prefer to do, and why?

[NetworkGroover]

I have a tendency to want to be lazy so I'd probably just create routed links. With /31s  you don't chew up too many IP addresses and just make sure my load-balancing algorithm is on point for the type of traffic I have. Plus you know your L2 domain stops hard at the access switch.

But I haven't spent a single day in an operational networking role, so I'm probably just talking out of my arse. ;P

If I were in an operational role though, I'd want to test this in a lab environment with each option, see how they recover from failures, etc. and weigh the pros/cons before making a definitive decision.  That's due diligence.

[Otanx]

I prefer /31s and ECMP. The main reason is my access switch will be uplinked to two agg/distro switches. If I use port channels then I need some kind of MLAG/VSS/VPC. Anyone doing that knows it is never a perfect solution. You have to deal with split-brain, and weird fail-over scenarios. With routed links everything just works.

-Otanx

[wintermute000]

routed ECMP is awesome but You need routed access ( never seen IRL outside of hyperscale) or some kind of VXLAN overlay including design of how North South traffic flows. And the default gateway + MLAG design. It's a new ballgame.

[jason.copas]

@LynK

What devices are you running at the access layer?  Do they have the processing power to support multiple routed interfaces + the routing protocol,  or will they get bogged down under the load?

I guess that doesn't truly answer your question.   But if I was running something like large stacks of 3750's at the access layer with multiple stacks behind on L2, I'd be tempted to run port-channels.  If my access layer was a 4500 series chassis switch with nothing behind it, I would be more likely to run multiple routed links.

Sent from my Nexus 6 using Tapatalk

[LynK]

This is strictly a Hypothetical. Lets say 4500-x at the edge going to 7k/9k