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New Member

Multilinking

Hi All,

Just a "quick one"

Is there any point to using Multilinking with just one serial link ?

I think that LLQ would be enough to get voice running fine on a single serial link...

What do you think.....

Fraser

7 REPLIES
Hall of Fame Super Bronze

Re: Multilinking

> Is there any point to using Multilinking with just one serial link ?

No.

> I think that LLQ would be enough to get voice running fine on a single serial link...

Yes.

Hall of Fame Super Gold

Re: Multilinking

Edison, indeed for circuit speeds of less than 256 kbps, you may need LFI that is based on MLP.

So the answer would be, "sometime".

Hall of Fame Super Bronze

Re: Multilinking

Less than 256kbps ? Gasp. Sorry, I've been spoiled :)

Hall of Fame Super Gold

Re: Multilinking

Do some networking in developing countries, and you will see how spoiled we are :)

Re: Multilinking

Well, yes there is a point, if you consider a byproduct of one of its features. Multilink can fragment large packets, for example the biguns you get in FTP, into small chunks. Normally is does this so it can spread the chunks evenly across two or more links.

Now, voice is sensitive to delays. So if a voice packet gets stuck behind a large FTP packet on a slow-ish link, it can be bad news. But if the FTP packet has been broken into small chunks by the multilink protocol, and if the voice packet has absolute priority, then the voice packet can slip in between two chunks of the FTP packet.

That is why autoqos can decide to make a link "multilink" even if there is only one of them.

Kevin Dorrell

Luxembourg

New Member

Re: Multilinking

so say the link is less than 256k what I understand from LLQ should still place all voice packets in front of the larger Default-queue packets (FTP) or am I wrong ?

The delay or jitter for voice then would be still acceptable or not ?

New Member

Re: Multilinking

Hi

The queuing strategy is all software, so yes your voice packet will go in front of the large "ftp" packet. Problem comes in the hardware buffer, due to the serialization delay on the serial link. The voice will have to wait until the whole "ftp" packet has been clocked on line, if the large "ftp" packet fills the hardware buffer. Thus voice will suffer from jitter and "break up".

Best practice is to implement LFI links > 768K, although I found using it on links > 512K works for me.

Options of implementing LFI includes ppp multilink, and frame-relay (FRF.12)

Regards

Phillip

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