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Author Topic: Nortel 8600 issue (unicast and broadcast problems)  (Read 1878 times)

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Offline jhoward

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Nortel 8600 issue (unicast and broadcast problems)
« on: May 03, 2014, 07:02:47 PM »
I'm hoping someone here can help me sort out a problem I am having with a mixed network of 2 Nortel ERS8600s (REL and Ruggedcom (now Siemens) 1500/1501 switches running ROX 2.2 with a few switches at 2.4.3.

There are 2 8600s located at hub buildings functioning as our core.

There are 60 Ruggedcom 1500/1501s functioning as layer 2(capable of layer 3) field switches.

The field switches are configured in a ring/daisy chain, passing from switch to switch to one of the Nortels, then leaving that Nortel and going switch to switch to the second Nortel.

There are 6 rings, each varying from 8-13 switches per ring.

Each ring has a single VLAN. Each Nortel has a copper blade (1G) assigned to VLAN1, with the rings being 2-7.

The switches are connected to each other with single mode fiber to 1G sfps.

RSTP is enabled with 1 Nortel functioning as the root bridge and the second Nortel functioning as the back up.

All the field switches are using a VRRP gateway that the master is the root for RSTP, and the backup is the backup for RSTP.

For 2.5 years, this network has functioned flawlessly.

A few months ago, the customer wanted to add 27 IP cameras at existing field switch locations. These cameras are Cohu cameras, running 2 multicast and 2 unicast streams.

A new VLAN (8) was added to the Nortels and existing field switches and a new VRRP gateway for the devices.

The fiber ports at the Nortels were changed from access ports to trunked/tagged as well as the ports on the field switches.

IGMP snooping (passive) was enabled at all field switches with the fiber ports being router ports.

IGMP snooping was enabled globally on the Nortels but not PIM or DVMRP.

The customer complained of pixelation on 2 of the 27 cameras. The other 25 had no issues. The issues were not apparent at a mirrored port on the field switch that the cameras attached to. The issues were apparent on the Nortels (both on the unicast and multicast streams).

While troubleshooting the cameras, we experienced a storm on the Nortels. Previously if a field switch misbehaved, the Nortels would prune the offending port and troubleshooting the source was fairly simple. Now, with a VLAN residing across all of the fiber ports, both Nortels will go to 100% utilization and be unresponsive instead of shutting down the port. We have to physically disconnect the fibers to get the utilization down on the Nortels, then add them back 1 at a time.

The first storm we blamed on RSTP flooding being enabled and turned it off on the field switches.

We don't know the cause of the second (they were 2 weeks apart).

1. What steps can I take to try to prevent the storms.

2. Is the pixelation possibly a saturation issue? Would MSTI help?

Thanks in advance!