3Com MSR 50 Series, Руководство по настройке

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Frame Relay Compression 253
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Ensure that both local device and remote device have been encapsulated with
frame relay protocol.
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If two devices are directly connected, check the local device and remote device
to ensure that one end is configured as frame relay DTE interface and the other
end as frame relay DCE interface.
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Ensure that the LMI protocol type configuration at the two ends is the same.
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If the above conditions are satisfied, enable the monitoring function for the
frame relay LMI messages to see whether one Status Request message
correspond to one Status Response message. If not, it indicates the physical
layer data is not received/sent correctly. Check the physical layer. The
debugging fr lmi command is used to enable the monitoring function for
frame relay LMI messages.
Symptom 3:
The link layer protocol is up, but the remote party cannot be pinged.
Solution:
1
Ensure that the devices at both ends have configured (or created) correct address
mapping for the peer.
2
Ensure that there is a route to the peer if the devices are not in the same subnet
segment.
Frame Relay
Compression
This section covers these topics:
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“Overview” on page 235
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“Configuring FRF.9 Compression” on page 254
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“Configuring FRF.20 IP Header Compression” on page 254
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“Configuring FRF.20 IP Header Compression” on page 254
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“Frame Relay Compression Configuration Example” on page 255
Overview Frame relay compression technique can be used to compress frame relay packets
to save network bandwidth, reduce network load and improve the data transfer
efficiency on frame relay network.
The device supports FRF.9 stac compression (referred to as FRF.9) and FRF.20 IP
header compression (IPHC), which is referred to as FRF.20.
FRF.9
FRF.9 classifies packets into two types: control packets and data packets. Control
packets are used for status negotiation between the two ends of DLCI where
compression protocol has been configured. FRF.9 data packets cannot be switched
before the negotiation succeeds. If the negotiation fails after 10 attempts to send
FRF.9 control packet are made, the negotiating parties stop negotiation and the
compression configuration does not take effect.
FRF.9 compresses only data packets and InARP packets; it does not compress LMI
packets.