Issue Description
Customer complaining that after inserting a /32 static route only with outgoing interface and without specifying the next-hop, packet loss occur.
Handling Process
Requested from customer the following output:
<Huawei> display diagnostic-information
transparent.gif Solution
#
interface 40GE1/0/6:4
undo portswitch
ip address 172.X.38.22 255.255.255.0
device transceiver 40GBASE-COPPER
Customer configuration was before like this :
[ac-2-1] ip route-static 172.X.38.18 255.255.255.255 40GE1/0/6:4
After configuring the static route in this way problem was solved:
[ac-2-1] ip route-static 172.X.38.18 255.255.255.255 40GE1/0/6:4 172.X.38.18
[ac-2-1] ip route-static 172.X.38.18 255.255.255.255 172.X.38.18
If we do not configure next-hop for a static route with a multi-access outgoing interface like Ethernet, it will be considered an incomplete route
entry.
If the next-hop is not specified in the static route, the next-hop in FIB it will be the interface’s address as the next-hop, in our case 172.X.38.22, which is not a valid next-hop or forwarding path.
When the packet is received for that destination it will be sent to CPU for further processing, because the route it matches does not have a next-hop and because Ethernet it’s a multi-access network segment, so it can’t rewrite the packet because it is missing Layer 2 information for the next-hop.
Next-hop is required to be configured on multi-access interfaces like Ethernet in this case for the CE to be able to rewrite the packets at Layer 2 correctly.
So, missing the 'next-hop' in your configuration caused unexpected behavior on the CE so from here is also the packet loss.
