AIS AI2524 Transmit Error Protocol Data Units ERPDUs, Control Redirect Protocol Data Units RDPDUs

Chapter 9: AI2524 OSI/CLNP Configuration Steps

Set the Congestion Threshold

If a router configured for CLNS experiences congestion, it sets the congestion-experienced bit. You can set the congestion threshold on a per-interface basis. By setting this threshold, you cause the system to set the congestion-experienced bit if the output queue has more than the specified number of packets in it.

In interface configuration mode, set the congestion threshold:

clns congestion-threshold number

Transmit Error Protocol Data Units (ERPDUs)

When a CLNS packet is received, the routing software looks in the routing table for the next hop. If it does not find one, the packet is dis- carded and an error protocol data unit (ERPDU) is sent.

You can set an interval between ERPDUs. Doing so reduces band- width if this feature is disabled. When you set the minimum interval between ERPDUs, the Cisco IOS software does not send ERPDUs more frequently than one per interface per ten milliseconds.

In interface configuration mode, transmit ERPDUs:

1. Send an ERPDU when the routing software detects an error in data PDU; this is enabled by default.

clns send-erpdu

2. Set the minimum interval, in milliseconds, between ERPDUs. clns erpdu-intervalmilliseconds

Control Redirect Protocol Data Units (RDPDUs)

If a packet is sent out the same interface it came in on, a redirect pro- tocol data unit (RDPDU) also can be sent to the sender of the packet. You can control RDPDUs with one of these actions:

z By default, CLNS sends RDPDUs when a better route for a given

	host is known. You can disable this feature. Disabling this feature
	reduces bandwidth because packets may continue to unnecessarily
	go through the router.
	clns send-rdpdu
	z You can set the interval times between RDPDUs.
	clns rdpdu-interval milliseconds
	Warning: SNPA masks are never sent, and RDPDUs are ignored by
	the Cisco IOS software when the router is acting as an IS.
August 1997	Page 9-55
2524UM