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Author Topic: story ~ a weird experience with nortel ethernet routing switch  (Read 4149 times)

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Offline cacids

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Hello Dudes,

I hope everyone is fine. Today is Monday and everyone in office started with reading newspapers and checking mails and online deals. Suddenly, one lady came to me "is it something wrong with network?" It's one the thing I hate to listen  :D I quickly checked syslog alerts folder and it was clean. Then, bunch of people came to me and the whole network is down - network drives, internet etc..

I went to comms room and checked physical connectivity first. It looks fine but no alerts. The most weird thing - I was able to browse the Internet. I jumped on to Avaya 5530 and blindly checked IST status. It was down. That's it. But, hang on - the weird list goes on. We have two 5530 in stack as primary and secondary, also they are OSPF neighbor. From secondary, i can see primary as an OSPF but can't ping. Also, for IST, the link trap was enabled and no notifications from syslog server. how come? I ran to comms room again to check out IST ports 25 and 26. I saw port 25 was green and blinking but port 26 was green and stable. I thought it's froze. I power cycled the switch and everything turned to normal.

But now, I am flash-backing the story and looking for answers. Is it a bug? why didn't get the notification? why ospf neighbor was up and not pinging?

platform details
Ethernet Routing Switch 5530-24TFD
 *** HW:32       FW:6.0.0.15  SW:v6.2.4.011


« Last Edit: July 11, 2013, 10:22:53 PM by cacids »


Offline cacids

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Re: story ~ a weird experience with nortel ethernet routing switch
« Reply #1 on: May 19, 2013, 10:11:52 PM »
Upon investigation, I came to Michael's this https://forums.networkinfrastructure.info/nortel-ethernet-switching/ethernet-routing-switch-5530-odd-behavior/article but there is no license issue. I checked and there is no expiry date.

Offline TankII

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Re: story ~ a weird experience with nortel ethernet routing switch
« Reply #2 on: May 20, 2013, 11:15:09 AM »
I vaguely remember this being a bug-fix in 6.2.5.
Not 100% sure though.
We have an IST pair of 5698's on 6.2.5 without issue.  Went from 6.2.2 to 6.2.5.

TankII

Offline cacids

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Re: story ~ a weird experience with nortel ethernet routing switch
« Reply #3 on: May 20, 2013, 08:13:56 PM »
Thanks for reply Tankll.

This is what I am finding so far - looks like the IST process between the two IST core switches may have failed. As there is redundant connection between core switches, it should have kept operating. This is why I think the actual IST process may have failed. Any thoughts on this?

Offline Telair

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Re: story ~ a weird experience with nortel ethernet routing switch
« Reply #4 on: May 21, 2013, 12:49:43 PM »
We had IST failure issues with 5632's on v6.2.4 code that Avaya told us that there were significant fixes for problems in the v6.2.5 and later code.  v6.2.6 seems to be a happy place right now for my IST'ed switches.

Offline Michael McNamara

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Re: story ~ a weird experience with nortel ethernet routing switch
« Reply #5 on: May 23, 2013, 06:23:34 PM »
I'm running 6.2.6 software on 4 pairs of ERS 5530s in an IST configuration and so far no problems.

Only upgraded about 3 weeks ago though from 6.1.5 software.
We've been helping network engineers, system administrators and technology professionals since June 2009.
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Offline cacids

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Re: story ~ a weird experience with nortel ethernet routing switch
« Reply #6 on: May 23, 2013, 09:29:19 PM »
Thanks Michael.

I have confirmed that it's not hardware related issue. Initially, I thought to replace XFP but that's not the case. The issue is with configuration. The IST on core switch 1 went down but didn't generate any alerts.

I am trying some solutions below:
  • Configure SLPP [Simple Loop Prevention Protocol on both core switches. Do I need to enable SLPP source guard? If so, where? I think on edge switches?
  • Enable Rate limit of 10% for Broadcast and Multicast traffic. I am not confident about this as it might affect the performance. What do you think?

please feel free to add your thoughts and suggestions. I will keep you all posted.

Thank you.

Offline cacids

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Re: story ~ a weird experience with nortel ethernet routing switch
« Reply #7 on: June 24, 2013, 09:50:06 PM »
Hello Guys,

This issue happened again but it was bit different. The IST and SMLT were UP. But, it was intermittent loss between core 1 and core 2. I was able to ping core 1 from 2 for a minute and then not. The internet [data traffic] didn't have any issue. But, nortel phones were keep booting after a minute. Most strange thing was, I didn't see any alerts from Syslog server. The only alert I observed was from DNS server, which was UP and DOWN.

Not sure what's the root cause. Any ideas?

Offline cacids

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Re: story ~ a weird experience with nortel ethernet routing switch
« Reply #8 on: July 11, 2013, 10:22:15 PM »
Update: I would like to thank all who were involved in this thread. Yes, firmware version v6.2.4 is not stable with IST. I have upgraded both core switches with v6.2.6 and so far, it's doing fine.

Cheers,