From: Yigit Zorlu (yigitzorlu@xxxxxxxxx)
Date: Sat Mar 09 2002 - 18:18:42 GMT-3
Hi,
MTU cases are not clear in my mind in DLSw. Please look at my notes below
taken from recent mails of the list;
Scenario 1:
(TR)--- R1---serial--- R2 ---ethernet---R3---(TR)
TCP:
In this case TR interface on R1 and R3 will have MTU of 4K. Maximum path MTU
is 1500(ethernet). So for TCP we configure " ip tcp mtu-path " and lf will
end up to be 516 (because next higher lf is 1470 and when you add to it
diffrent headers packet size will exceeed MTU of 1500) . Now when a device
connects to it partener by sending an explorer, eventually maximum lf will
get negotiated to be 516.
FST:
for similar reasons we will have to manually configure to be 516.
Scenario 2:
ethernet---- R1 ---serial--- R2 --- serial --- R3 ---(TR)
IF LOWEST MTU OF THE PATH IS 1500 OR IF LF ENDS UP TO BE 1470 EVERYTHING
WILL BE SIMILAR TO SCENARIO 1. BUT IF LF IS LARGER THEN:
TCP:
Maximum frame will be negotiated to 1500 ( as this is the maximum mtu
ethernet can support).
FST:
Have to be cofigured to the best LF. If LF is lager than what cloud can
support, although peers will be formed but, sessions will not establish.
My questions are ;
In which cases I have to manually set up MTU and where (local-peer statement
or remote-peer statement or interface ??)
If there is an ethernet connection in the DLSw peer path and both ends are
TR then will I have to set MTU 516 ??
In which cases DLSw negotiates for the MTU ??
Regards,
Yigit
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:56:58 GMT-3