Alcatel Carrier Internetworking Solutions Switch/Router 用户手册

Page 26-5

In multiple group configurations, AutoTracker rules can be deployed to strategically support 
the relay function. Two types of AutoTracker IP policies are appropriate for 

DHCP

 environ-

ments. The first is the IP protocol policy that puts all IP type frames into a single 

VLAN

 regard-

less of network address. The second is the 

IP

 network policy that groups 

IP

 users based on 

their specific IP address. 

Besides AutoTracker rules, the network administrator must be aware that some network envi-
ronments may contain 

DHCP-

ready and non-

DHCP

 clients. Such configurations are supported 

by the switch’s 

BOOTP

 relay function. 

In source route environments (where 

VLAN

 framing type is set for source routing) and 

DHCP

 

clients are not directly attached to the switch but have one or more bridges between them, 
the 

 file must be modified so that replies from the 

DHCP

 server can get through the 

bridge. 

Typically a router caches the client’s 

RIF

 information for source routing when the client 

responds to an 

ARP

, but if the client does not yet know its 

IP

 address it cannot reply to an 

ARP

 and no 

RIF

 information is cached on the router. Unicast replies to the client before the 

RIF is cached are discarded by the router. Forcing the 

BOOTP

 reply to be broadcast elimi-

nates this problem.

Use the 

 command to make this change to the 

 file (see Chapter 7, “Managing 

Files,” for instructions on using the 

 command).

Add the following command:

Reboot the switch to force the broadcast. Replies from the 

DHCP

 server to the client will be 

broadcast from the router as 

STE

 or 

ARE

 packets so they can be sent through the bridge. 

Authentication clients may use 

DHCP

 to get an IP address. For Telnet authentication clients, 

an IP address is required for authentication. The DHCP server may be located in the default 
group, an authenticated group, or both. If authentication clients will be getting an IP address 
from a 

DHCP

 server located in an authenticated group, a 

BOOTP

/

DHCP

 relay should be set up 

using the 

 command described in this chapter.

In addition, the router port address of the authenticated group must also be configured for 
the relay through the 

 command. See the Authentication Services chapter of the 

the Switched Network Solutions User Manual for more information about this command.