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de 30 + gatway half duplex

Why is the ethernet interface on the DE 30+ half duplex ?

On cisco equipment I have found running 10meg full duplex to work without errors.

I have been experiencing issuses where the interfaces

of a cisco 2948g l3 is connected to a 2611 ethernet interface at half duplex 10 meg.Our callmanagers hang directly of the layer 3 switch.Users have been experiencing major problems at remote site.The phone

is seeing MaxJtr at around 900 -1200 and RxLost 60 -120 depending of course on the length of the call.

I have seen excessive collisions on the interface as well as deferred packets on the 2611.Does this meen that all rtp udp traffic will be dropped as the router cant buffer it all ?.As the carrier is busy (deferred packets)I'm assuning it would drop udp packets being connectionless with no ack's.

3 REPLIES
Cisco Employee

Re: de 30 + gatway half duplex

Can you please elaborate on the network map? Also, what are the phones at the remote site calling to when they have the problem? Is it all phones at the main site, only offnet phone numbers, or calling each other?

New Member

Re: de 30 + gatway half duplex

The network map is Centralised call proccessing at Sydney 1

Remote site Syd 2 connected by 2 X hdsl links 4mbit and a 2mbit link.the 2611 is at SYD1 the other end has 2621. The phone issues are related to PSTN and on net calls.Though The problems are primarily at the remote site Syd 2.Sydney 1 does experience lost packets when communicating with Syd 2 As the calls at the central site connect straight from 3548xl access switches to the layer 3 voice quality is excellent when its local obviously having a fully switched 100mbit network helps this aspect.Currently we are useing policy based routing to route calls rtp over the wan therfor matching on min max pct lenghts of 214bytes as well as access lists that specify calls to the pstn gateway,to use the dedicated voice path.I changed the interfaces to full duplex from the 2611 to layer 3 and call quality is much better.The design is not good so any suggestios would be appreciated.

Sh proc cpu is low on both routers and statistics from Netflow,mrtg,seafelt show that both links are under utilised and there is ample bandwidth available.

Remote site is only 350 metres up the road and there are no errors on the serial interfaces of both routers.Dave shortly I will be forced to converge the data and voice on the 1 link as I have no choice.

There are obviously various differnt configurations for QoS does anyone have suggestios as to which queing method would be suitable for this WAN topology and why ?Our company grew very quickly and not enough emphasis was put on design sorry none.This has been an ongoing problem for roughly a year and I have spoken and had a Cisco engineer in who said to run wfq on ethernet interfaces this proved and achieved nothing.And when I went to get back to the guy he had been retrenched so I haven't had much success.Resources are limited and no test equipment is available.So suggestions here from successful implementations of QoS in simmilar scenarios would be invaluable.

Thanks in Advance.

Cisco Employee

Re: de 30 + gatway half duplex

You should use LLQ for QoS across the WAN link. I guess I am still a little confused on exactly which devices the packets go through on an IP phone to IP phone call between SYD1 and SYD2. Probably if you have a Visio diagram or other drawing that you could provide it would be quite helpful. You should probably open up a TAC case and provide this to them.

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