Cisco Systems BC-281 manual Displays content of group, local and remote caches, Explorer Firewalls

Configuring Data-Link Switching Plus

DLSw+ Configuration Task List

To display the contents of the reachability caches, use the following command in privileged EXEC command mode:

Command	Purpose
Router# show dlsw reachability [[group [value]	Displays content of group, local and remote caches.
local remote] [mac-address [address]
[netbios-names [name]

Use the group keyword to display the reachability information for the border peer.

Explorer Firewalls

An explorer firewall permits only a single explorer for a particular destination MAC address or NetBIOS name to be sent across the WAN. While an explorer is outstanding and awaiting a response from the destination, subsequent explorers for that MAC address or NetBIOS name are merely stored. When the explorer response is received at the originating DLSw+, all explorers receive an immediate local response. This eliminates the start-of-day explorer storm that many networks experience. Configure the dlsw timer command to enable explorer firewalls. See the “Configuring DLSw+ Timers” section on page 310 for details of the command.

To enable explorer firewalls, use the following command in global configuration mode:

Command	Purpose
Router(config)# dlsw timer	Tunes an existing configuration parameter.
{icannotreach-block-time netbios-cache-timeout
netbios-explorer-timeout netbios-group-cache
netbios-retry-interval
netbios-verify-interval sna-cache-timeout
explorer-delay-time sna-explorer-timeout
explorer-wait-time sna-group-cache
sna-retry-interval sna-verify-interval}time

NetBIOS Dial-on-Demand Routing

This feature allows you to transport NetBIOS in a dial-on-demand routing (DDR) environment by filtering NetBIOS Session Alive packets from the WAN. NetBIOS periodically sends Session Alive packets as LLC2 I-frames. These packets do not require a response and are superfluous to the function of proper data flow. Furthermore, these packets keep dial-on-demand interfaces up and this up time causes unwanted per-packet charges in DDR networks. By filtering these NetBIOS Session Alive packets, you reduce traffic on the WAN and you reduce some costs that are associated with dial-on-demand routing.

To enable NetBIOS DDR, use the following command in global configuration mode:

Command	Purpose
Router(config)# dlsw netbios keepalive-filter	Enables NetBIOS DDR.

The following command enables NetBIOS DDR:

dlsw netbios keepalive-filter

	Cisco IOS Bridging and IBM Networking Configuration Guide
BC-300	78-11737-02