Chapter 13: AI2524 Frame Relay Configuration Steps
August 1997 Page 13-39
2524UM
interface buffers and lead to higher pa ck e t ra te l oss for both user dat
and routing updates.
To avoid such problems, you can cre at e a special broadcast queue for
an interface. The broadcast queue is managed independently of th
normal interface queue, has its own buffe rs , and has a configurable
size and service rate.
A broadcast queue is given a maximum t ransmission rate (throughput)
limit measured in both bytes per second and packets per second. The
queue is serviced to ensure that no more than this maximum is pro
vided. The broadcast queue has priority when tr an s mit t ing at a rate
below the configured maximum, and hence has a guaranteed minimum
bandwidth allocation. The two transmission rate limits are intended to
avoid flooding the interface with broadcasts. The actual transmission
rate limit in any second is the first of the two rate l imi ts that is reached.
In interface configuration mode, create a broadcast queue:
frame-relay broadcast-queue

size byte-rate

packet-rate

Configure Payload Compression
You can configure payload compression on point-to-point or multi
point interfaces or subinterfaces. Payload compression uses the stac
method to predict what the next character in the frame will be. Becaus
the prediction is done packet-by-packet, the dictionary is not con
served across packet boundaries.
Payload compression on each virtual circuit con su me s ap proximately
40 kilobytes for dictionary memory.
zConfigure payload compression on a specified multipoint inter-
face or subinterface:
frame-relay map

protocol protocol-address

dlci
payload-compress packet-by-packet
zConfigure payload compression on a specified point-to-point in-
terface or subinterface:
frame-relay payload-compress packet-by-
packet
Configure TCP/IP Header Compression
TCP/IP header compres sio n, as de sc ribed by RFC 1144, is designed to
improve the efficiency of bandwidth use over low-speed serial links.