Alcatel Carrier Internetworking Solutions Switch/Router 사용자 설명서

Page 26-1

UDP

 is a connectionless transport protocol that is used for applications that do not require the 

establishment of a session and end-to-end error checking, such as email and file transfer. This 
chapter describes the 

UDP

 relay function in the switch, which allows 

UDP

 broadcast packets 

to be forwarded across groups and 

VLAN

s that have IP routing enabled. The 

UDP

 relay allows 

you to use nonroutable protocols in a routing environment. (For information about IP rout-
ing, see Chapter 25, “IP Routing.”)

♦ Note ♦

BOOTP

/

DHCP

 relay has previously been available on 

the switch. It is now part of an expanded feature that 
includes relays for 

NetBIOS

 and generic services. 

The relay may be configured for the following services: 

• Bootstrap Protocol (

BOOTP

)/Dynamic Host Configuration Protocol (

DHCP

)

•

NetBIOS

 Name Server (

NBNS

)

•

NetBIOS

 Datagram Distribution Server (

NBDD

)

• Generic applications, such as Trivial File Transfer Protocol (

TFTP

)

The 

UDP

 services, their corresponding well-known port numbers, and configurable options 

on the switch are listed here. 

Routing Information Field (

RIF)

 stripping is required for transparent bridge ports in source 

route environments and may also be useful in non-source route environments. 

In a source route environment, where 

RIF

 stripping is enabled for transparent bridging to 

Ethernet, 

UDP

 relay clients should not be more than one switch away from the 

DHCP

 server. 

(In 

RIF

 stripping, 2 bytes are stripped from the 

RIF

 and each bridge adds 2 bytes to the 

RIF

. 

Packets with a 

RIF

 greater than 2 bytes are discarded.)

BOOTP/DHCP

67/68

Next-hop address (up to 8)
Forward delay
Maximum hops

NBNS

137

Next-hop address (up to 8)
Forwarding VLANs (up to 32)

NBDD

138

Next-hop address (up to 8)
Forwarding VLANs (up to 32)

Generic

user-configured

Next-hop address (up to 8)
Forwarding VLANs (up to 32)