At 06:16 22/02/2002 +0800, Eric So wrote:
>The proprietry HDLC will give you headache if you want
>to change the platform in the future.
Really? It takes about 10 seconds to change encapsulation. In all my years
running a major ISP network, it has never been a problem for me, or anyone
else I've worked with or for.
>FR encap gives you sub-interface numbering which acts
>as an identifier to network devices through a proper
>indexing scheme.
Useful on a DS3 link which is clear channel... What's wrong with the
sequential numbering used in IOS for interfaces - I really don't see the
difference.
In my past life we'd done performance characterisation of the different
encapsulations, and for packet throughput there was little to choose
between PPP and HDLC. Frame was marginally less good, ATM came well down -
don't have the numbers any more, unfortunately. We stuck with HDLC unless
there was a need to use PPP - it kept life simple...
philip
-->-e > >On Thu, 21 Feb 2002, Gyorfy, Shawn wrote: > > > Since the topic exploded, what are your opinions on encapsulation of leased > > line DS3s. We currently use Frame Relay for out Point to Point DS3 > > connections. Personally, I don't know why we use FR as our encapsulation, > > and so the question to all. If you are running Cisco to Cisco, would it be > > wise to run HDLC or PPP? Our DS3s' here are hardly maxed out, 15% or > so, so > > I'm not complaining about the few extra bits I can squeeze out them but > > maybe that 15% can shrink to 10% with less overhead. Opinions or examples > > of life appreciated. > > > > Thanks > > > > shawn > > > > -----Original Message----- > > From: Iljitsch van Beijnum [mailto:iljitsch@muada.com] > > Sent: Wednesday, February 20, 2002 4:28 PM > > To: Jon Mansey > > Cc: nanog@merit.edu > > Subject: Re: Cisco PPP DS-3 limitations - 42.9Mbpbs? > > > > > > On Wed, 20 Feb 2002, Jon Mansey wrote: > > > > > OMG! Arent we missing the point here? What about never running links > above > > > 60% or so to allow for bursts against the 5 min average, and <shudder> > > > upgrading or adding capacity when we get too little headroom. > > > > > And here we are, nickel and diming over a few MBps near to 45M on a > DS3... > > > > And why not? Obviously there is a reason why they're not upgrading, > > because there is plenty of traffic to fill up a second or faster circuit > > if packets are being dropped because of congestion. (Which has not been > > confirmed so far.) > > > > There shouldn't be any problems pushing a DS3 well beyond 99% utilization, > > by the way. With an average packet size of 500 bytes and 98 packets in the > > output queue on average, 99% only introduces a 9 ms delay. The extra RTT > > will also slow TCP down, but not in such a brutal way as significant > > numbers of lost packets will. Just use a queue size of 500 or so, and > > enable (W)RED to throttle back TCP when there are large bursts. > >
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