Avaya Configuring BOOTP Services Instrukcja Użytkownika Pobierz pdf (Strona 43)

SNMP, BootP, BootP/DHCP Relay, and DHCP Server Concepts

308644-15.1 Rev 00

2-11

If, however, the client and the server are on different physical networks, a BootP

relay agent (also known as a BootP gateway) must forward BootP packets to their

correct destinations. When you configure a Nortel Networks router for BootP

services, the router acts as a BootP relay agent. Figure 2-3

illustrates how BootP

works when the client and the server are on different physical networks.

Figure 2-3. BootP Client and Server on Different Physical Networks

The client transmits a BOOTREQUEST packet to the IP broadcast address

(255.255.255.255). The router receives the BOOTREQUEST packet at an

interface that you configured to receive BOOTREQUEST packets (an input

interface). If the BOOTREQUEST packet has an address other than

255.255.255.255, the router drops the packet.

Figure 2-4

shows the fields in the BOOTREQUEST and BOOTREPLY packets.

3. Server transmits

BOOTREPLY

packet to BootP

relay agent.

1. Client broadcasts

a request to boot from a

remote server

(BOOTREQUEST).

4. BootP relay

agent transmits

BOOTREPLY

packet to client.

2. BootP relay

agent transmits

BOOTREQUEST

packet to servers

on other networks.

Client

Server

Router

(BootP relay agent)

SNM0003A

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Avaya Configuring BOOTP Services Instrukcja Użytkownika Strona 43