Management Domain Packet Walk-Through - Paradyne 8540 Network Configuration Manual

Packet Walk-Throughs

Management Domain Packet Walk-Through

9-4
When ES1 pings NSP1:
1. ES originates a packet addressed to 155.1.2.2. Because they are both on the
155.1 network, ES1 ARPs to map NSP1's IP address into a MAC address.
2. The RTU receives the broadcast ARP request from ES1.
3. The RTU replies to the ARP request with its own MAC address (proxy ARP).
4. After ES1 receives the ARP reply, it sends the packet to the MAC address of
the RTU.
5. Upon receiving this packet, the RTU forwards it to the 8546 DSL card over its
DSL interface.
6. When the 8546 DSL card receives this packet, the 8546 DSL card consults
its routing table to determine how to route the packet. Since a source route is
defined for ES1 (route #1), the 8546 DSL card forwards the packet to the
router (151.1.3.1), which is the next hop.
7. The router then forwards the packet to NSP1.
NSP1 then issues a reply to the ping.
1. The NSP sends the ping reply packet addressed to 155.1.3.4.
2. By normal means, the packet arrives at the router.
3. Because the router has an interface with an address 155.1.3.1 (on 155.1.3
subnet), it ARPs for 155.1.3.4.
4. Because the 8546 DSL card has a host route (marked PA=y) for 155.1.3.4, it
responds to the ARP request with its own MAC address (proxy ARP).
5. Then, the ping reply is sent directly to the 8546 DSL card.
6. The 8546 DSL card then consults its routing table to identify the next hop to
forward the packet. Since a host route is defined for ES1 (route #2), the RTU
135.1.3.3 is used as the next hop.
7. The 8546 DSL card then forwards the packet over the DSL port to that RTU.
8. Upon receiving the packet, the RTU forwards the packet to its 10BaseT port
because it has a host route for ES1.
To examine how data packets flow through the management domain, an example
of the DCE Manager workstation 1 (WS1) performing a ping to the HotWire RTU
is used. The following is assumed:
A host route to the RTU (135.1.3.4) exists on the MCC card. (This is
generated automatically.)
A static route to WS1 (135.1.1.1) is configured on the 8546 DSL card.
November 1997 8000-A2-GB21-20