tl;dr: My CRS305 configured as a basic switch doesn’t seem to be passing DHCP discover broadcast frames from one port to another when there’s a VLAN involved, regardless of whether VLAN filtering is on or off. I’m hoping this is a simple newbie config mistake but I haven’t been able to figure out where I’m going wrong…
View of the world from the perspective of the CRS305:
- sfp-sfpplus1: Router (CCR2116) that is sending DHCP discover frames tagged with VLAN 320
- sfp-sfpplus4: WAN link (ONT) that provides Internet link on VLAN 320
I have confirmed that the router part seems to be working correctly: if I use torch or port mirroring to observe traffic that the CRS305 receives on SFP port 1, I see DHCP discover frames with VLAN 320.
But what I do not see is those same frames going out SFP port 4, neither using torch nor using port mirroring. It’s as if the CRS305 is not forwarding the broadcast to port 4 even though I think it should be, based on its config.
I’ve tried the config two ways. First I tried with no VLANs configured and vlan-filtering=no. My assumption was that in this case, the switch would forward broadcast frames on all VLANs to all ports (as in, it wouldn’t filter any of them out, like it says on the tin). When that didn’t work, I also tried configuring VLAN 320 on the switch and making it a tagged port on ports 1 & 4, but that didn’t work either.
Basic config:
/interface bridge
add name=bridge
/interface bridge port
add bridge=bridge interface=sfp-sfpplus1 # ...repeat for ports 2-4
/interface ethernet switch
set 0 l3-hw-offloading=yes
/ip address
add address=192.168.11.2/24 interface=bridge network=192.168.11.0
Changes I made for the alternate config using VLANs (rest same as above):
/interface bridge
add name=bridge vlan-filtering=yes
/interface bridge vlan
add bridge=bridge tagged=bridge,sfp-sfpplus1,sfp-sfpplus4 vlan-ids=320