Hello,

I know this is minimal information, but I just set up MPLS on our network, i'm using LDP, the routing protocol is OSPF. Currently it seems to work fine other than a couple of odd issues i'm getting. I've gone through mpls mtu checks on all the active interfaces to make sure they are correct. For some reason bandwidth tests using tcp from router to router seems to run slow, a max of 3mbits, and I seem to be getting just as slow speeds from our servers on a connected interface at the edge router. All of our clients work fine out to the internet though from various connected interfaces throughout the network. I'm not even sure where to look for this issue anymore.

If you need more info, ask, any help is appreciated.

Thanks.

hello

few questions

1) what RB are you using
2) what is the mtu for IP - L2 - MPLS on interfaces
3) are you using same router for mpls and testing ?

Thierry

EDGE
R1
| \
R2---R3
| |
R5---R4---R6
/ | /
| R9
| |
\ R10


R1 - Link Technologies PowerRouter V3 i7 x86 MTU: IP-1500 L2-not listed* MPLS-1508all
R2 - Link Technologies PowerRouter 732 x86 MTU: IP-1500 L2-9014 MPLS-1508all
R3 - Routerboard AH1100x2 MTU: IP-1500 L2-1598 MPLS-1508all
R4 - Link Technologies PowerRouter 732 x86 MTU: IP-1500 L2-9014 MPLS-1508all
R5 - Routerboard 493AH MTU: IP-1500 L2-1520 MPLS-1508all
R6 - RouterBoard 1100AHx2 MTU: IP-1500 L2-1598 MPLS-1508all
R9 - Linktechnologies PowerRouter 732 x86 MTU: IP-1500 L2-9014 MPLS-1508all
R10 - RouterBoard 493AH MTU: IP-1500 L2-1520 MPLS-1508all

*Trying to find out from the vendor.

This is a wisp so there are bridged license ptp links in between the routers. When contacting the vendor they informed me the l2mtu on those is 9014.

So we have several hundred customer connected to each router, all speeds are fine out through the internet. When doing tcp bandwidth test router to router they are bad ~3mbit, all speeds to our webserver which is directly plugged in to the edge are bad through the network but fine out to the internet.

Thanks.

on powerrouter v3 to have more than 1500 you insert the desired mtu in ip mtu
as you have more than 1508 on al llinks i would advise to

setup l2mtu to max of the min of all interfaces you go through
setup mpls mtu to l2mtu - 8
setup ip mtu to 1500

we have some AHx2 with BGP VPLS and we route 300 Mbps with no problem

0 R name="ether1 - Dialup" mtu=1500 mac-address=00:60:E0:4A:88:CA arp=enable>
disable-running-check=no auto-negotiation=yes full-duplex=yes
cable-settings=default speed=100Mbps

1 R name="ether2 - Webserver" mtu=1500 mac-address=00:60:E0:4A:88:CB
arp=enabled disable-running-check=no auto-negotiation=yes
full-duplex=yes cable-settings=default speed=100Mbps

2 R name="ether3 - DSL/Switch" mtu=1500 mac-address=00:60:E0:4A:88:CC
arp=enabled disable-running-check=no auto-negotiation=yes
full-duplex=yes cable-settings=default speed=100Mbps

3 R name="ether4 - Tim Hunt" mtu=1500 mac-address=00:60:E0:4A:88:CD
arp=enabled disable-running-check=no auto-negotiation=yes
full-duplex=yes cable-settings=default speed=100Mbps

4 X name="ether5 - Open" mtu=1500 mac-address=00:60:E0:4A:88:CE arp=enabled
disable-running-check=no auto-negotiation=yes full-duplex=yes
cable-settings=default speed=100Mbps

5 X name="ether6 - Open" mtu=1500 mac-address=00:60:E0:4A:88:CF arp=enabled
disable-running-check=no auto-negotiation=yes full-duplex=yes
cable-settings=default speed=100Mbps

6 R name="ether8 - Wireless Network" mtu=1500 mac-address=00:60:E0:4A:88:D1
arp=enabled disable-running-check=no auto-negotiation=yes
full-duplex=yes cable-settings=default speed=100Mbps

7 X name="ether7 - Open" mtu=1500 mac-address=00:60:E0:4A:88:D0 arp=enabled
disable-running-check=no auto-negotiation=yes full-duplex=yes
cable-settings=default speed=100Mbps

8 R name="ether26 - ISP2" mtu=1500 l2mtu=9014
mac-address=00:60:E0:53:1C:24 arp=enabled disable-running-check=no
auto-negotiation=yes full-duplex=yes cable-settings=default
speed=100Mbps

9 R name="ether9 - ISP1" mtu=1500 l2mtu=9014
mac-address=00:60:E0:53:1C:23 arp=enabled disable-running-check=no
auto-negotiation=yes full-duplex=yes cable-settings=default
speed=100Mbps



On the PowerEdge V3 I have no way to change the l2mtu nor does it list what it is? I changed the ip mtu to a little higher on the wireless network interface which links to the next mpls router but it dropped everything. Currently network wide the ip mtu is 1500 and the mpls-mtu is 1508. It seems that when I turn ldp of on the Power V3 everything works right, so i'm pretty sure this is the issue.

It's odd because I had mpls on and was able to access winbox just fine on the edge, then we loaded the full routing tables and I lost winbox. Turning off mpls made it accessible again, so it seems there must be an issue l2mtu wise.

I guess it probably dropped everything because ospf had mtu issues after that. What do you suggest I set the interfaces to on either side?


This is the interface on the edge.

6 R name="ether8 - Wireless Network" mtu=1500 mac-address=00:60:E0:4A:88:D1
arp=enabled disable-running-check=no auto-negotiation=yes
full-duplex=yes cable-settings=default speed=100Mbps


And the one on the opposite side

0 R name="ether1 - Deanstone PTP" mtu=1500 l2mtu=9014
mac-address=00:90:FB:31:22:C4 arp=enabled disable-running-check=no
auto-negotiation=yes full-duplex=yes cable-settings=default
speed=100Mbps


I've read the l2mtu is conditioned by the ip mtu atleast on the edge side.

for mtu in powerrrouter v3 just type 9000 for example in MTU field ( replace 1500 ) if you are on daugther cards
or you can use the 2 standard copper ports whith default mtu aat 9514

for ospf all IP MTU must be same on both sides

best would be to have

IP MTU =1500
MPLS MTU = 1512 at minimum
L2 MTU = MPLS MTU + 4

so on powerouter just put value of L2 MTU in over mtu existing value

we are using ROS v5.22

The PowerRouter v3 has a 8 port GigE Modle

All the ports on that module show no l2mtu / max mtu



It's greyed out.

If I set the mtu higher than 1500, i'm changing the ip mtu on that interface, so if I set it to 9000 i'd have to set the mtu on the opposite interface to 9000.


So I don't see how I could have

IP MTU =1500
MPLS MTU = 1512 at minimum
L2 MTU = MPLS MTU + 4


Sorry, i'm just a bit confused and kind of angry the PowerRouter module doesn't report the l2mtu, that would be much easier.

yes
all is 9000 on our network so did not matter for this
we are using trunks with vlans so we can setup the port to 9000 and the vlan to 1500

I have exactly the same problem using the PowerRouter V3. L2MTU is not configurable in all the module cards, I have both fiber and electrical modules.
I tried to change the IP MTUs and MPLS MTU but continue to have the problem. Where you able to fix this problem?

Hello

i just setup ip mtu to 9000 on ether port
and i use trunking with vlan

hop it helps

I tried to use a VLAN between the V3 and the RB1100AHx2 but had the same problem. It works fine if I substitute the V3 with a PowerRouter 732.

can you try using TE tunnels and avoiding LDP
but this implies ospf
more over what are ROS version on routers

1530 is really the minimum MPLS mtu you want to set on an MPLS network if you want to use all of the ATOM feature set like EoMPLS and VPLS. It's needed to be able to hand off a 1500 byte segment to the edge

I never did get this resolved actually, raised the MTU's, messed around with a lot of different setups, the fix was to not use mpls on the v3, it was the edge so it wasn't a huge deal. The whole core of the network runs mpls just fine. I was hoping possibly fastpath may help if they ever get a stable release of ROS6, but i'm not even clear on whether fastpath will work mpls on x86, so who knows.

I do have traffic engineering working on everything though, including the v3 on the edge.