Alcatel Carrier Internetworking Solutions Switch/Router External BOOTP Relay

BOOTP/DHCP Relay
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External BOOTP Relay
The BOOTP relay may be configured on a router that is external to the switch. In this applica-
tion example the switched network has a single AutoTracker Group configured with multiple
segments. All of the network hosts are DHCP-ready, meaning they obtain their network
address from the DHCP server. The DHCP server resides behind an external network router,
which supports the BOOTP relay functionality.
One requirement for routing DHCP frames is that the router must support BOOTP relay func-
tionality to be able to forward DHCP frames. In this example, BOOTP relay is supported within
an external router, which forwards request frames from the incoming router port to the outgo-
ing router port attached to the Omni Switch/Router.
DHCP Clients are Members of the Same VLAN
The external router inserts the subnet address of the first hop segment into the DHCP request
frames from the DHCP clients. This subnet address allows the DHCP server to locate the
segment that the requesting client resides on. In this example, all clients attached to the Omni
Switch/Router are DHCP-ready and will have the same subnet address (130.0.0.0) inserted into
each of the requests by the router’s BOOTP relay function. The DHCP server will assign a
different IP address to each of the clients. The switch does not need an IP address assigned
and all DHCP clients will be members of either a default VLAN or an IP protocol VLAN.
Omni Switch/Router
12345678
123456
Group 1
DHCP Clients
130.0.0.11 130.0.0.12
DHCP Clients
130.0.0.14
130.0.0.13
DHCP Clients
130.0.0.15
DHCP Server
125.0.0.1
125.0.0.2
External
BOOTP
Relay
DHCP Client