SPB - Explain Technology - SMLT

[marti571]

Hello
We have actually 2 Nortel 8306 on network core interconected by IST link
Multiple ERS4548 Distributions Stacks are linked whith the cores by SMLT.

We had a commercial presentation about SPB
We understood interest about SPB, no tag configuration by port, security, easy to propagate VLAN through big network.

But we have question
Does SPB replace MLT/SMLT ??

If we will change 8306 by VSP 700

Will we be forced to set SMLT before add SPB over ?

Or is what the SPB takes care of itself inteconnexion? without SMLT ?

[zakabog]

SPB and MLT/SMLT are different technologies. From the marketing material I found it looks like SPB is simply a replacement for STP where it will detect a path through the network and bring down any of the other paths that create a loop, unless the detected path goes down in which case the other paths might come up.

MLT and SMLT are for aggregated links, where you want more throughput and greater resiliency (since you have multiple links that are up, rather than waiting for one to go down and the other to take over.)

[friedlgoeran]

The two technologies - SPBM and Switch Clustering (SMLT) - are not competing one with another, instead we went the way to implement a special SPBM feature, called Split Backbone Edge Bridge, that allows a Switch Cluster - in your case two ERSs 8600/8800 - to act as the Edge of the Fabric and still dual hone attached to it devices, like adge switches or servers, using some sort of Link aggregation. By doing this, we don't lose the active-active attachment to the fabric (SPB network) and do not require, that the Edge for dual homing must support SPBM. Hope this clarifies the situation a bit. The configuration of such a split BEB pair is well explained in the technical configuration guides and varies for different platforms.

[toehit]

Hi: Just deployed VSP's with Split-BEB (2 nodes, two locations each) on the core side with Virtual IST (vIST) link between the nodes.

I'm going to tackle your questions 1 by 1 and hopefully it helps.

Q) Does SPB replace MLT/SMLT ??

No, SPB is more of a transport - allowing multi-path active-active links across a fabric. It's power is really in it's ability to flexibly do edge-only provisioning. So if you ever went through the annoyance of tagging a vlan across, say 3-4 routers, now you build one vlan on each edge and attach it to an iSID, the fabric carries it multi-path.

It's relation to MLT's (SMLT) is complimentary. You still can build a SMLT edge to service L2 switches via SMLT. As referenced above it's technically called a "Split Backbone Edge Bridge" or Split-BEB, but it's equal to SMLT in most ways, and superior in others.



Q) If we will change 8306 by VSP 700, Will we be forced to set SMLT before add SPB over? Or is what the SPB takes care of itself inteconnexion? without SMLT

-Not sure what model you are going with 7000's or 7200's, but depending on what your setup is, you might find it best to simply replace the SPB core day one. Found a guide on Avaya's site - will try to find it again today.

If you want the edge resilience of SMLT you'll have to build the 7x00 series out as SMLT(S-BEB) to protect against hardware failure. You won't get around configuring SMLT characteristics such as:
-RSMLT
-Local VLAN's
-MLT's
-IST (Note: a vIST is now possible that no longer occupies traditional ports as it once did and uses the fabric to keep the cluster in sync, it's also extremely simple once it's set up).


The Guide that helped me with my design and implementation was: NN48500-617 (Shortest Path Bridging Technical Configuration Guide), it's an engineering Doc on Avaya's site.

Page 74 of that guide shows where SPB and SMLT are cooperative to one another. This guide gave me a bundle of configuration examples that I was able to adapt and mash together to build out what I wanted.

Anecdotally - we lab tested 6 SPB units (2 clusters and 2 stand alone 4450's) and tried to actively break the fabric for a couple of months (intentional configurations of NNI's between 'sites', vmotion across active links and yanking the links). It just worked. We've been production for about 2 months.

Hope that helps.

Best of luck! If I can provide you any help based on our testing I'm here.