topic Re: Cisco 881 half duplex issue in Routing and SD-WAN

Cisco 881 half duplex issue

mze — Mon, 02 May 2022 10:39:56 GMT

cisco 881 issue

Re: Cisco 881 half duplex issue

Richard Burts — Tue, 22 Mar 2022 14:14:27 GMT

Do you by any chance configure the speed of the WAN interface of 881?

Re: Cisco 881 half duplex issue

Flavio Miranda — Tue, 22 Mar 2022 14:16:20 GMT

Looks like there´s some misundestanding about IEEE 802.3u on this devices. Did you try auto in both ends?

Re: Cisco 881 half duplex issue

balaji.bandi — Tue, 22 Mar 2022 14:18:57 GMT

Can you post show version - there may be some bug around some codes.

also post show run interface x/x and show interface x/x

Can you connect Laptop to Router see what is speed it negotiate on the same port ?

Re: Cisco 881 half duplex issue

Umesh Shetty — Tue, 22 Mar 2022 15:15:09 GMT

What you described in the first part of your products blem is an expected behaviour. When one end is set to auto negotiate and the other is hard coded the auto negotiate end does not have the means to know what the other end is set to and hence sets itself to the default i.e. half duplex

The other part is interesting though.

- If you did not use a Cross over cable , disabling auto negotiate can turn of mdix auto negotiate and hence the interface could be down.

- This can also be a cable issue ?

- Possibly also an interface problem.

Would be helpful if you send a show run of the interfaces. Also as earlier said can you connect the 881 to a laptop and see if auto negotiate works there ?

Re: Cisco 881 half duplex issue

Joseph W. Doherty — Tue, 22 Mar 2022 15:16:18 GMT

Like @Umesh Shetty, I agree too believe that's expected behavior, i.e. full-duplex<>auto results in auto using half-duplex.

For the latter, that might be whether the 881 supports auto-MDI/MDI-X, which on some other devices, when supported, requires port to be in auto mode. I.e. on some device, if auto mode disabled, you need to use the correct cable (straight through, or cross over) to interconnect devices.

Your ADVA doesn't support auto? (Almost, if not all, network hardware vendors, at least this century, recommend using auto<>auto.)

Re: Cisco 881 half duplex issue

paul driver — Tue, 22 Mar 2022 21:39:13 GMT

Hello

@mze wrote:

When setting the WAN interface on the 881 to fixed full duplex the connectivity gets lost.

What exactly are you doing when setting this interface, Are you actually hardcoding both the speed AND duplex, Also what speed is the ADVA box procurred at, the 881 seems to only support only fast ethernet?

Re: Cisco 881 half duplex issue

mze — Mon, 02 May 2022 10:41:01 GMT

thanks

Re: Cisco 881 half duplex issue

mze — Mon, 02 May 2022 10:41:37 GMT

Hi thanks for reply

Re: Cisco 881 half duplex issue

mze — Mon, 02 May 2022 10:42:08 GMT

Hi thanks for reply

Re: Cisco 881 half duplex issue

mze — Mon, 02 May 2022 10:40:28 GMT

thanks

Re: Cisco 881 half duplex issue

Umesh Shetty — Wed, 23 Mar 2022 09:45:25 GMT

What is the ADVA interface set to ?

Re: Cisco 881 half duplex issue

mze — Wed, 23 Mar 2022 09:50:37 GMT

Full duplex .

Re: Cisco 881 half duplex issue

Richard Burts — Wed, 23 Mar 2022 16:13:18 GMT

Thanks for confirming that the 881 is auto for both speed and duplex. Can you tell us whether perhaps the ADVA configures the speed of its interface or is it set for speed auto?

Re: Cisco 881 half duplex issue

Elliot Dierksen — Wed, 23 Mar 2022 16:30:15 GMT

If you force duplex on one side, you MUST force it on both sides. Forcing duplex means it doesn't participate in negotiations. Thereby the "auto" side MUST default to half because it gets no response to the negotiation request.