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Re: Telnet/SSH intermittent hanging on new Itanium servers

 
roose
Regular Advisor

Re: Telnet/SSH intermittent hanging on new Itanium servers

Volker - Yes, we currently have 6 network ports on the server (3 combo cards), and only 3 of them (EIB0, EID0 and EIF0) actually has physical connection to the LAN. The other 3 (EIA0, EIC0 and EIE0) are open. I am attaching the tcpip show int command output for your reference.
Volker Halle
Honored Contributor

Re: Telnet/SSH intermittent hanging on new Itanium servers

Roose,

o.k. - only ONE interface (LLA0, LAN Failover) configured for TCPIP. And I guess you're using the SAME interface for DECnet as well (please check with $ MC NCL SHOW CSMA-CD STAT * COMM PORT - should show LLA). Then this pretty much rules out any physical or data link layer problems.

If you login to your Itanium systems via SET HOST from the Alpha and then do a TELNET LOCALHOST on the Itanium system, do you see the hangs as well ?

Volker.
Cass Witkowski
Trusted Contributor

Re: Telnet/SSH intermittent hanging on new Itanium servers

Itaniums support auto-negotiation. Please make sure that your LAN switch is configured to auto-negotiate.

roose
Regular Advisor

Re: Telnet/SSH intermittent hanging on new Itanium servers

Volker - I have attached NCL command result and it does show LLA. I tried to do what you recommended of doing a set host from Alpha then doing a Telnet localhost, but the response time is serverely degraded that I am no longer able to observe if the session hangs at all.

Cass - Let me clarify: Are you suggesting that we leave the network interfaces to be at Autonegotiate? Currently, we have asked our Network admin to set the switch ports where our Itanium servers are connected to to be full-duplex, 1Gbps. This is due to our experience before with our Alpha's wherein autonegotiate for the switch port and network interfaces introduced some session hangs as well for interactive processes. Next week, I am asking HP engineer to come in and help us statically set the NIC cards on the servers to 1Gbps, full-duplex from the console level.
Volker Halle
Honored Contributor

Re: Telnet/SSH intermittent hanging on new Itanium servers

roose,

a TELNET localhost on your rx7640 shows bad performance ? Could you try this from the OPA0: console terminal oof the rx7640 to find out, if this problem is a local TCPIP issue ?

Note that you have configured DECnet to run on 4 LAN interfaces in parallel, according to your previous responses EIB, EID and EIF are connected to the network. So whenever you connect to that system using SET HOST, you really don't know, which LAN interfaces are being used ! For TCPIP you know it's only LLA0 ! This makes troubleshooting a little bit more complicated, becasue there could be a problem on LLA0, which you might not see when using DECnet, which may use another interface !

Have you configured LAT on the rx7640 ? If not, why not start LAT on the rx7640 on just ONE lan interface (start with LLA0: with DEF LAT$DEVICE LLA before @LAT$STARTUP), then SET HOST/LAT from the Alpha, then try TELNET localhost. You could then easily try each of the other LAN interfaces with LAT as well.

Volker.
Steven Schweda
Honored Contributor

Re: Telnet/SSH intermittent hanging on new Itanium servers

> [...] This is due to our experience before
> with our Alpha's [...]

Were those gigabit Ethernet interfaces? I
thought that auto-negotiation was a required
feature in gigabit Ethernet.

> Please make sure that your LAN switch is
> configured to auto-negotiate.

I'm with him. Same for the VMS systems. If
you actually observe a gigabit Ethernet link
failing because of an auto-negotiated
mis-match, _then_ you might think about
trying to out-smart the automation. Until
then, I'd trust the automation.
Proliant VMS San Mgrs
Frequent Advisor

Re: Telnet/SSH intermittent hanging on new Itanium servers

Roose,

What is the switch at the other end?

I agree with Steven & Case. The NICs used in AlphaServers are often based on a very old Digital chip, and that had serious problems with auto-negotiation; Alpha's were almost always configured with 100mbps/Full Duplex at both ends.

I have always had good luck with autonegotiation for any gigabit interface, and I thought that setting was required. I'm somewhat surprised that your network staff did not discuss this with you in detail...

Let us know if you test the autonegotiation for gigabit, and if that fixes the problem. Thanks.

Carl
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