Running Milrotik Group of Routers , all peered with OSPF and BGP.
Have VPLS tunnel setup between 2 routers and link works, is able to pass ping’s no problem.
Continuous Ping works fine
The problem happens when trying to use certain network resources. https starts but then goes to blank screen.
the setup of the tunnel themselves is very simple just putting in the source and destination ip’s (similar to the EIOP Tunnels)
I have enabled LDP on the loopback address ..
The tunnels come up and then I bridge them to Local interfaces
Any Ideas where the config may need to be tweeked?
Thanx
Router A
0 R name=“PRIVATE” mtu=1500 l2mtu=1500 mac-address=02:19:29:4D:12:2F
arp=proxy-arp disable-running-check=no remote-peer=a.b.c.31
vpls-id=0:1 cisco-style=no cisco-style-id=0 advertised-l2mtu=1500
pw-type=raw-ethernet
Router B
0 R name=“PRIVATE” mtu=1500 l2mtu=1500 mac-address=02:C4:EC:DC:4C:5C
arp=proxy-arp disable-running-check=no remote-peer=A.B.C.D.29
vpls-id=0:1 cisco-style=no cisco-style-id=0 advertised-l2mtu=1500
pw-type=raw-ethernet
----------- Note on one side the vpls connection is bridged into a VLAN--- Below is the appropriate interface info
5 R ;;; PRIVATE-VPLS
VLAN107 1528 enabled 107 ether12
Your MPLS MTU is too small, it needs to be a minimum of 1508 to get a basic “raw ethernet” style VPLS tunnel running. The L2MTU on the physical interface will also need to be a minimum of 1508bytes as will the path-MTU e.g. every hop in between the two routers needs to support 1508byte frames.
the 2 routers are directly connected with switches no other routers in between
I have set the mpls mtu to be larger 1522 and the l2mtu to is defaulted to 1600..
router to router pinging the loopback addresses (Bridge) It fragments at 1500 and through the vpls tunnel it fragments at 1450
on each side I have the vpls configured to bridge to a local port or a vlan.. do I need to modify the mtu’s on them also?
currently those are all set to be 1500
Hi all,
I have a similar problem and, I think, the problem is olso MTU but I don’t know where…
Look at attached network layout:
rb1-core, rb2-core, rb-core-tower-a and rb-core-tower-b run MPLS with MPLS-MTU interface configured to 1526 in according of my previous (post replys.
On tower sides the eth1 of each rb1200 are the only interface configured in mpls interfaces and are linked with ethernet cable to each rb411 (where the wlan1 and eth1 are bridged).
Olso on core side the eth1 of each router os x86 (i have virtual machine with router os for x86) are the only interfaces configured in mpls interface and are linked with ethernet cable to each rb411 (where the wlan1 and eth1 are bridged).
The mpls run over an ospf routing between routers (rb1-core, rb2-core, rb-core-tower-a and rb-core-tower-b) that annunce the 192.168.17.0/24 network, on all router there are olso a loopback interfaces used for transport address (ldp interface) with 172.16.0.x/32.
There are olso configured vpls between rb-core-tower-a and rb1-core/rb2-core and rb-core-tower-b and rb1-core/rb2-core
From tower side this vpls are bridged with other eth interfaces of rb1200 where are linked other rb411 for customer collection (customer use pppoe-client with sxt to open connection).
From core side the vpls are bridged to a standalone bridge where is in listen a centralized pppoe-server (i prefer to have pppoeserver on a virtual interface like bridge who not have problem of link up/down).
Evrithing work fine but some user tell me that few site (some governament web site or free webmail service) don’t load.
The workaround to work, but don’t use vpls/mpls, is to insert eth1 of tower side in to the bridge that contain vpls.
The only thing that I’m not able to change is the L2MTU value of eth1 of core side (the virtual machine with router OS).
What is wrong? I have some difficult to comprend MTU End to End!!
What command can i use to troubleshoot mtu problem?
No you do not need to modify the MTU on the LAN side ports. You only need to have it larger on the ports that are running LDP.
If you cannot pass packets greater than 1500bytes there is a definite MTU problems on the interfaces running LDP. I typically set the MTU to 1526 on my LDP interfaces and set the MPLS MTU to this as well. This will allow you to transport vlan tagged frames inside VPLS without control word.
I was able to get mine to work by dropping down the VPLS MTU to be 1440 for the time being I’m leaving it be. and will work more on this via test bed… it would be good it there was a basic config in the Mikrotik site/manual/wiki on how to set this up.
something as basic as 2 routers connected together with ethernet and passing a vpls connection
with exact configs … the wiki is vague on alot of stuff
