Management and Configuration Guide K/KA/KB.15.15

Figure 70 Layer 3 forwarding (IP unicast) in DT topology
Another example in Figure 71 shows Layer 3 (IP unicast) forwarding in a DT topology. The packet
is sent as follows:
1. Host 2 sends a packet to Switch C.
2. Switch C performs a lookup in the routing table and determines that the default gateway IP
address is 10.0.0.1.
3. Layer 2 lookup determines that the outgoing interface is the DT port.
4. Hashing determines that the trunk member chosen is DT_SW_2 and the packet is sent there.
5. DT_SW_2 determines that the packet needs to be sent over the ISC link to DT_SW_1 based
on the MAC address.
6. DT_SW_1 performs a lookup and determines that the packet goes to Switch A.
The packet is only forwarded if the outgoing interface is not a DT port, or if the outgoing DT port
does not have an active interface on the peer switch.
About configuring peer-keepalive links 167