I came across a bulletin from Nortel just recently that I thought was important enough to post here in case anyone reading this has 8648GTRs installed in his/her ERS 8600 chassis. I have about 10 of them installed at multiple locations, primarily in core switches feeding large server farms and other high-speed devices. I don’t believe I need to extol the pains that auto-negotiation sometimes reaps on network engineers. While modern network switches and NICs are definitely more compatible with respect to auto-negotiation, problems sometimes still arise. It would seem that a duplex mismatch on one port of the 8648GTR could potentially impact performance on up to 24 ports. Here’s the text from the bulletin;
Background:
An Ethernet port can operate either in Full or Half Duplex mode. A duplex mismatch is created when using inconsistent settings for duplex mode, i.e. full duplex on the port and half duplex on the connected device (or vise versa). This situation is most likely created when using inconsistent and inappropriate settings for auto-negotiation, i.e. auto-negotiation enabled on the port and disabled on the device connected to the port (or vise versa). The duplex mismatch problem can be corrected by setting consistent duplex mode on both the port and the connected device when hard setting the duplex mode or by enabling auto-negotiation on both the port and the connected device, when using auto-negotiation.
Ethernet ports of most devices today have auto-negotiation enabled as the default setting. When a device with auto-negotiation disabled is connected to a port that has auto-negotiation enabled, the port is not able to detect the duplex setting of the connected device and falls back to half duplex thus potentially causing a duplex mismatch. A duplex mismatch will cause physical layer errors and performance degradation of the connection. Any mixture of auto-negotiation enabled on one-side and auto-negotiation disabled on the other side is an “unsupported” configuration. The setting on both sides of any connection must match for proper operation. A problem has been identified when there is a duplex mismatch on one or more ports of an 8648 GTR module. For an 8648 GTR module, a duplex mismatch may cause complete communication issues on the port with the mis-matched duplex or occasionally on the entire lane (Port 1-24 or Port 25-48) that contains the port with mismatched duplex. The module can be recovered from the situation when physically reseated, but for complete recovery the mis-configuration must also be corrected. Correcting the duplex setting configuration alone will not recover the communication loss until the module is reseated as well.
Analysis:
A duplex mismatch may cause communication loss on a port or an entire lane of an 8648 GTR module. When there is such a communication loss, the debugging commands show that the ingress stats look normal with all traffic ingressing the impacted port(s) and the MAC addresses learned in the Forwarding Database Table for the devices connected to the port(s), but no traffic egressing the port(s).
Recommendations:
Nortel recommends proper configuration of auto-negotiation whenever possible to prevent a duplex mismatch situation. To avoid a duplex mismatch, auto-negotiation must be enabled on the port as well as the device connected to that port.
You can find a copy of the bulletin in PDF format right here. Interestingly there are quite a few restrictions and issues with the 8648GTR that I should probably discuss them here when the time allows.
Nortel is also in the process of releasing v5.0 software for the Ethernet Routing Switch 8600 along with four new IO modules (cards); 8612XLRS, 8634XGRS, 8648GBRS and 8648GTRS. I hope to talk about those in the very near future.
Cheers!
Does anybody know something about Nortel VGMCs and Ciscos switchs speed/duplex mismatchs?!
Why do you think you’re having issues?
The ELAN port is fixed at 10Mbps half duplex while the TLAN port can negotiate 100Mbps full duplex.
You can use the following commands from the IPL prompt on the VGMC card;
tLanSpeedSet Set the TLAN ethernet speed
tLanSpeedGet Get the TLAN ethernet speed
tLanDuplexSet Set the TLAN ethernet duplex mode
Good Luck!
Hi,
We have a lot of issues like described in this announcement, and it has leaded to freeze to 24 ports on the GTR module – Only solution we had was to reset (physical extraction-insertion) of the module
We are waiting for a solution from Nortel – Seems to be incredible that a defectuous server can freeze a complete module on such expensive devices …
Hi gby,
I would definitely have to agree with you. I only have a few 8648GTR cards in my network but I knew something was up when some folks from Nortel told me there would be a new 48 port 10/100/1000 carts (8648GTRS) released in conjunction with 5.0 software. It certainly sounds like you are suffering for the problem reported in the bulletin. I sometimes find that saving yourself works better than waiting for Nortel.
Good Luck!
Hi
Is there a way to force a PortAdminSpeed to a 1000 mbps on the 8648 GTR blade?
Because whenever we try to force it it comes up with this error: rcPortAdminSpeed.473: Cannot change port speed on this type of port.
Plaese help.
I have a Nortel Module 8634XGRS. I wan to do the port speed hard setting to full 1000mbps on ethernt port but it gives me a error (rcportadminduplex.259:cannot set adminsped 1000 as per 1EEE.). Can we change the port speed to hard Set Full duplex 1000MBPS.
Hi Sandeep,
A few questions if you will… what code are you running? What port are you trying to change? Are you configuring the switch from the CLI or from JDM?
You generally can’t set the port speed on GBIC/SFP ports to anything other than Auto/Auto or 1000/Full.
Cheers!
Have anyone idea how to setup a 10/100/1000 port of a 8648GTRS card fix to 1000 full duplex.
I get the same error (cannot set admin speed 1000 as per 1EEE…..).
I remember someone commenting on this problem in the past… what version of software are you running?
Cheers!
7.1.0.0 code
Are you trying to set the speed via EDM or via CLI?
I seem to remember an issue (older software) where using JDM would fail but using the CLI interface would work.
Cheers!
Hi,
I already tried with CLI, EDM and the same happen.
I also tried upgrading the system to 7.1.0.1 (the last one) and the same happened.
cheers
this is the message:
Can’t set admin speed on this port as per IEEE 802.3ab 1000Base-T standard with auto-neg set to false a port speed of 1000M is not allowed.
You are correct… according to the IEEE 802.3ab is not part of the standard. Here’s an excerpt from an HP document;
That’s just wild… so you need to stick with auto-negotiation or perhaps modifying the CANA options might also be an option.
Now, i do not understand something.
Why does not it happen with 8648GTR modules?
cheers
That’s a good question… perhaps time to reach out to an Avaya resource.
Hi Michael(How r u)
One of my clint wants to implement IPV6 in their campus network.
Pls confirm what release of software is required on 8606 if existing release(4.1) will support it.
As 8606 will remain connected to existing 420/425 and 2526 T switches
and some servers on IPV4, do we need to have a dual stack implementation .
Kindly suggest best transition policy to comply.
Hi Sandy,
You’ll need to upgrade your ERS8600 to 7.x software to get full IPv6 support. There are some hardware requirements to upgrade so I would suggest you review the release notes at a minimum.
Good Luck!
Thanks Michael
I think IPv6 only runs on R module….m i right..????
You are right in that 7.x software will only run on R/RS modules… and only 7.x software fully supports IPv6.
There is some support for IPv6 in 5.x software but it’s not complete.
Cheers!
Can we use nortel 425/420/2526 series switches as l2 with ipv6 with help of dual stack implementation on core.