we run HDLC on DS3 and we max at about 40.something too not sure why, i just assume theres either overhead in the frames somewhere or that the cards arent designed to run at line speed we run HDLC, c-bit and CRC16 on PA-2T3+.. be interested if anyone knows how to get the missing 10% :) Steve On Wed, 20 Feb 2002, Ehud Gavron wrote:
At a recent consulting opportunity, a client was only getting 40.9Mbps on their DS-3 (clearchannel DS3 over OC12 to the IP provider). (PA-2T3 to PA-2T3, unloaded CPU, drops occur when peak octets out per sec/8=40.9M)
The client asked us why 40.9 was less than 44.210.
The IP provider indicated that "Cisco told us the maximum theoretical rate of an interface doing DS-3 with PPP encapsulation is 42.9."
I can't find documentation to the 42.9. I can't find documentation that indicates that the PPP overhead is somehow magically excluded from the IfOctetsIn and Out... I can't find documentation as to why 40.9 is the observed rate.
Frankly, all my DS-3s (HDLC encap) go up to 44.210, so I was hoping I could share in the collective wisdom of NANOG readers who have DS-3s to IP providers, and can provide real observed feedback.
Please reply privately. Please let me know privately if you want a summary. Thanks!
Ehud Gavron gavron@wetwork.net
-- Stephen J. Wilcox IP Services Manager, Opal Telecom http://www.opaltelecom.co.uk/ Tel: 0161 222 2000 Fax: 0161 222 2008