L3 MLT IP Address

[nightwatch]

Is it possible to create a Layer 3 MLT with an IP address similar to how you do in a Cisco equipment. The goal of this is to remove STP from the routed ports so that when the links go down they don't affect the current STP topology.

[Michael McNamara]

I don't believe you can do it like a brouter port but you can certainly do it at the VLAN level.

Just create a new VLAN, create an MLT and associate the specific ports with that MLT. Assign an IP address to the VLAN and your off and running. You'll need to use a switch that supports routing.

Good Luck!

[nightwatch]

But that's exactly what i have right now. The problem is that when the MLT ports go down in the other site, they after the Spanning Tree Topology.

I read in the documentation related to the brouter possibility:
The Ethernet Routing Switch 8600 supports brouter ports. A brouter
port is a single-port VLAN that can route IP packets and bridge all
nonroutable traffic. The difference between a brouter port and a standard
IP protocol-based VLAN configured to perform routing is that the routing
interface of the brouter port is not subject to the spanning tree state of
the port. A brouter port can be in the blocking state for nonroutable traffic
and can still route IP traffic. This feature removes interruptions caused by
Spanning Tree Protocol recalculations in routed traffic.
Because a brouter port is a single-port VLAN, each brouter port decreases
the number of available VLANs by one and uses one VLAN ID.

This is what i want and simple interface to forward L3 traffic using OSPF.
Gonna investigate further. Thank You

[Michael McNamara]

What switch models are you working with?

You can't trunk brouter ports together, if you want to trunk multiple ports you need to create a MLT and then route at the VLAN.

If you want to use a single port then a brouter port will work fine.

Good Luck!

[nightwatch]

I'm using a cluster of 2 ERS8600. Software 4.1.7.1

I want to use multiple ports but I want to remove this Layer 3 MLT from the STG 1 so that if the links in the outside go down, the Spanning-Tree Topology in the Cluster doesn't get affected. This because obviously i don't need STP in Layer3 links.

To prevent situations like this:

NONE INFO Spanning Tree Topology Change. New Root bridge 00:21:ea:34:ab:01 for StgId = 1
SNMP INFO Link Down(8/48)
SNMP INFO Port 3/48 is an access port
SNMP INFO Link Down(7/48)

These links connect to an OSPF neighbor.

[Michael McNamara]

Why not just disable Spanning Tree on the ports?

[nightwatch]

what's the difference between disabling STP on those ports and removing them from stg 1?
Because when trying to remove them from stg 1 i get a warning that it will remove those ports from the vlan as well.

[Michael McNamara]

It's because VLAN1 is a member of STG 1 so the ports that are a member of VLAN1 need to be in STG 1.

Just disabled STP on both ports (make sure to-do the same on the other side of the link).

You'll also need to confirm that you have STP enabled globally.

Good Luck!