Check out this link it explains the problem:
http://www.cisco.com/warp/public/794/router_mtu.html
Most DSL/PPPoE CPEs have some form of packet interception to get
around this problem.
At 10:23 AM -0400 10/12/01, Andrew Herdman wrote:
>PPPoE drops the MTU down to 1492. Adjust to that and everything will be fine.
>
>Andrew
>
>On Wed, Oct 10, 2001 at 04:54:15PM -0700, Joe McGuckin wrote:
>> I'm using PPPoE on a 7206VXR300 to terminate about 100 active sessions.
>>
>> Basic connectivity and authentication is working. I am seeing some problems
>> with connecting to unix ftp servers. Downloads are slow and bursty
>>(for example,
>> an initial burst of traffic followed by several seconds on inactivity, then
>> another burst of traffic). Performing the downloads on the lan
>>downstream of the
>> pppoe router (but without using pppoe) produces a fast, continous download.
>>
>> Most of the end users are using PPPoE routers manufactired by
>>Netgear or DLINK.
>> I've demonstrated the problem with at least 2 different brands of routers.
>>
>> Does PPPoE cause problems with MTU settings?
>>
>> Any advice would be welcome!
>>
>> Thanks,
>>
>> Joe
>>
>>
>> --
>>
>> Joe McGuckin
>>
>> ViaNet Communications
>> 994 San Antonio Road
>> Palo Alto, CA 94303
>>
>> Phone: 650-213-1302
>> Cell: 650-207-0372
>> Fax: 650-969-2124
-- Scott A Silzer
This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:51 EDT