Hello, i need a small help regard a mpls lab i have created . CCR1036 is pppoe concentrator . After all configuration before to activate mpls i have done tests with ping do-not-fragment with 1588 value from every router 1100ahx4 in the scheme its ok . After this i activate mpls and create vpls tunels from each router to vpls concentrator i cant ping any more with higher mtu. what is strange that i lose bytes on every hop …
from the first 10.0.255.4 hop i can ping with do not fragment with 1582 , from second hop 10.0.255.5 with 1556 and from third hop 10.0.255.6 with 1552 .
Another thing happening is that if am passing trafic from last hop 10.0.255.6 ex bandwidth test 1mbps up / 1mbps down and during this test i bring down 2 tunels from 10.0.255.5 and 10.0.255.4 . the bandwidhth test stop pasing trafic for about 3-4 second and start again . this is strange becouse on vpls concentrator each vpls tunel is part of separate bridge and shoud not affect each other. maby im wrong . this is firt time for me in mpls , any help will be appreciated.
MTU test from tunnel on R1 2024
MTU test from tunnel on R2 1992
MTU test from tunnel on R3 1988
MTU test from tunnel on R4 1988
Router R1 R2 R3 R4 has same config, no extra rules why mtu change after every hop ?
Any one has similar config , maby im wrong or maby its normal to have all this changes on MTU but something is strange. why some routers has ony 4 byte difference some other has 26byte and the last one are the same considering its same config .
all routers have one interface in , one interface out and one interface on vpls bridge.
is this so hard to answer. mikrotik pls ask someone of your support team to have a look . i know its not a paid support but i think its a post with wide range of interes for many others.
i want to build a large network with 100-200 routers in mpls ,like a cloud in a city. a kind of grid with many possibile paths . I want to know if mtu is different or it will change after every hop it will be a problem calculating mtu size becouse topology may change becoue of OSPF and links drops and a shorter path with 5 hops can become longer ex with 10 hops in the middle and it will affect also mtu .
is it normal or am wrong with my calculations. ??
i want to solve this puzzle , we have example 10 routers in mpls . All routes has interface L2MTU 2028 , MPLS MTU 2028 and VPLS MTU2028. OSPF running , and every router has a single vpls tunnel to the router R1. as i have tested maximum usable MTU from each vpls tunnle on R2 will be 2024, on R3 will be 1992 on R4 will be 1988 on R5 will be 1988 .
R1 > R2 > R3 > R4 > R5 > R6 > R7 > R8 > R9 > R10
Question 1 mln usd . What usable MTU will we have at R6 , R7, R8, R9, R10 ???
Im trying to understand how MPLS in Mikrotik works and its is in interes of everyone i think.
I want to increase MTU but i am missing something, I have set l2MTU as 1598, MPLS MTU as 1550, and VPLS MTU as 1508, but cannot ping, did you change MTU on interfaces ?
