North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Cisco DS3 Questions..
There's no reason to use frame-relay encapsulation unless you're actually going through a frame network. For point-to-point circuits, from Cisco to Cisco, HDLC is the best choice, but it's proprietary (although Juniper has a Cisco HDLC mode). For anything else, I'd recommend PPP. -C On Thu, Feb 21, 2002 at 01:46:44PM -0500, 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:[email protected]] > Sent: Wednesday, February 20, 2002 4:28 PM > To: Jon Mansey > Cc: [email protected] > 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. -- --------------------------- Christopher A. Woodfield [email protected] PGP Public Key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xB887618B
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