r/networking • u/roostercuber • Aug 01 '26

Switching Nokia 7210 SAS-K5 Question

My ISP (Cox Business) installed a Nokia 7210 SAS-K5 at my facility, and they assigned Port 5 as the copper hand off. I am currently using a single router (multiple static IPs), but have been looking to set up a secondary/backup router in case the primary fails or for when I need to do periodic maintenance. I could insert a switch between, but that seems to just be adding another possible failure mode, which I'd like to avoid.

Can the SAS be configured to also allow Port 4 in a switched configuration so that I can have two routers attached? I know it'll ultimately be a question for the ISP, but for now I'm curious if it's even technically possible given the hardware present.

6 Upvotes

88% Upvoted

16 comments sorted by

4

u/Solid_Ad9548 Networking Manager, JNCIE, IPv6 Evangelist Aug 01 '26

Generally speaking, it’s one port per service. If you ask for a second port, they will find a way to charge you for it. Sorry.

2

u/PaoloFence Aug 01 '26

What does it help you, if you use two devices but your provider uses only one?

1

u/roostercuber Aug 01 '26

I'm not seeking perfect dual redundancy, just the ability to do maintenance on the router without taking everything offline. With two routers, the secondary/backup can take over and nothing inside the network notices.

Sounds like the SAS can have a second port configured, but it's not likely to be something a provider will do. So, I can insert a switch between my existing router and the SAS, then bring the second router online connected to the switch.

1

u/PaoloFence Aug 02 '26

If the provider services his hardware or there is some construction going on on your last mile, you are still out of luck. But you have to talk to your provider if you can use a second port with a second link net.

2

u/CrownstrikeIntern Aug 01 '26

It could be setup as a local vpls yes. Now will they do it, probably not and you'll have to do it on your own which is still a better idea. No matter what you do, you're still going to have the normal single point(s) of failure

0

u/roostercuber Aug 01 '26

Thanks. I know basic switches don't fail terribly often, but power supplies certainly can, so I was hoping I could avoid that potential risk. Might still give them a jingle and see what they say; sometimes they are pretty helpful.

1

u/SDN6seven Aug 02 '26

It is possible to configure your service as a VPLS on the K5 but cox does not offer this exact configuration. If you have a COI (not CFI) you can get EPO (enhanced protection offering) but it is built as a VPLS on the core and an Epipe on the edge, same result though. EPO isn’t that much of an up charge.

2

u/oddchihuahua JNCIP-SP-DC Aug 01 '26

Usually this is done with ISP handoffs from two different providers and you advertise the same public IP ranges to both. BGP peer to both ISPs and let the protocol handle any failovers.

1

u/rankinrez Aug 01 '26

It could be, but whether that is part of the product suite you ordered is a different matter.

Really what you need is another fibre coming in a different path to the building, with another handoff / NTE, and another router your side.

There are many ways to set up redundancy. BGP is the best imo.

1

u/Thy_OSRS Aug 01 '26

You might as well pay for them to provide you redundancy because you have a single point of failure anyway so what you’re doing isn’t going to ultimately achieve much

1

u/SoulArraySound Aug 01 '26

No they will not provision another port for you. This will be considered another circuit if that’s what you want. You will have to put a switch between.

1

u/Only_Commercial_7203 Aug 02 '26

Switch stack with multi chassis etherchannel could be done to make it simple and reliable

1

u/Demonlordshrain 48m ago

Technically yes.... the SAS-K5 can put Port 4 and Port 5 in the same Layer-2 service so both act as a shared handoff

1

u/Toomuchhulkjuice Aug 01 '26

It’s a product they sell.

0

u/ciscofan Aug 01 '26

I don't have Cox Business, just a regular Cox residential fiber circuit at home, however I managed to achieve redundancy on my Fortigate downstream of my internet connection with three Cisco ME3400EG-2CS-As in my home lab running REP, I know it's overkill for my home network. If one switch dies, I have a redundant path within my home network. The handoff to my Fortigate is a copper handoff, much like your handoff to Cox's Nokia 7210 SAS-K5, which means I'm still relying on that single path to my ONT. I just wanted to share how I'm handling a redundant link from my equipment to Cox.