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VSR bridge interface MAC Address

 
demain1
Occasional Collector

VSR bridge interface MAC Address

Hi, I'm seeing something which seems unusual when using the VSR ritual router, 

When I have an interface in route mode and create a sub-interface - I see normal behaviour in that the MAC address used for packets leaving the interface is the MAC address assigned from the VMWare vNIC, 

Expected behaviour config:

interface GigabitEthernet2/0
port link-mode route

interface GigabitEthernet2/0.2082
ip address 10.24.0.4 255.255.255.254
vlan-type dot1q vid 2082

If I have the interface in bridge mode and than add a tagged vlan to the interface, the mac address used seems to be a global system level mac address rather than the interface mac address:

Strange behaviour config:

interface GigabitEthernet1/0
port link-mode bridge
port link-type trunk
undo port trunk permit vlan 1
port trunk permit vlan 2081

The MAC address used for packets leaving the 1/0 interface can be seen using this command (there may be other ways to find this address)

dis lacp system-id
Actor System ID: 0x8000, cc3e-5f81-fa15

If I add a second interface in bridge mode - it also uses the same MAC adderess.

I'm tring to use a bridge / vlan so that I can control the VLAN using Openflow/SDN, I can't find a way to control a sub interface using SDN.

Does anyone know if, 

A - This is expected behaviour?

B - Is there any way to change this behaviour?

Thanks

 

 

1 REPLY 1
davidgrocke
Occasional Contributor

Re: VSR bridge interface MAC Address

Hey Demain1

I can't say with authority that it's expected, but all VLANs you create on the VSR1000 will use the system-ID. 

Sub-interfaces on network and firewall devices will inherit the burnt-in MAC or vNIC MAC on most, if not all vendors.  

You can change this by specifying the MAC address within the VLAN interface mac-address xxxx-xxxx-xxxx and I've noticed you can also spoof the inherited MAC on the vNIC. You do need to do this in certain scenarios, such as ESXi vDS with Forged Transmits set to "Reject". VMware recommend Forged Transmits to be set to reject to prevent MAC Spoofing of Ethernet frames, however, it does break Dot1Q packets when not using sub-interfaces (not just a HPE thing...). Changing Forged Transmits to "Accept" for the specific VM is acceptible, but admins will often miss this configuration when the environment changes or the VM is migrated, whereas the VSR1000 configuration is clearly visible in the current configuration.

 

I have to admit that I haven't tested this thoroughly, but I hope this helps.

 

Cheers

David Grocke