Alcatel Carrier Internetworking Solutions Switch/Router 사용자 설명서

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Configuring SPX Keepalive Spoofing
Page 27-30
Configuring SPX Keepalive Spoofing
The 
spxspoof
 command is used to enable and disable SPX Keepalive Spoofing on any or all 
WAN routing services. The use of this feature is explained below:
Novell’s SPX Keepalive Protocol, which is used by NetWare to maintain SPX connections 
between end nodes, can also consume significant network bandwidth and thereby incur 
unnecessary costs on expensive dial-on-demand, pay-per-packet WAN links. The Omni 
Switch/Router provides a SPX Keepalive Spoofing feature to prevent keepalive packets from 
keeping WAN links active when they are not otherwise needed for data transmissions.
The SPX Spoofing feature enables the switch to respond to client/server keepalive packets on 
the behalf of the remote clients/servers. SPX spoofing thereby effectively stops keepalive 
packets from crossing a WAN link while maintaining existing SPX connections.
SPX-Packet Tolerance Counting
NetWare’s SPX and SPXII watchdog and keepalive packets unfortunately are not labeled with 
a unique packet type. Therefore, valid acknowledge packets or window-update packets could 
be mistaken for keepalive packets. To prevent blocking of critical packets, a packet tolerance 
counting mechanism is employed by the Spoofing feature to count SPX packets.
When active, the Spoofing feature observes all watchdog and keepalive packets as they go 
between network endpoints. If successive packets are found to have the same sequence 
number, acknowledge number, and “alloc” number, spoofing will not begin until the speci-
fied SPX-packet tolerance count has been reached. Only watchdog packets which have the 
ACK_REQUSTED
 bit set will have an effect on the SPX-packet tolerance counter.
Once the specified tolerance count has been reached, spoofing of watchdog packets will 
begin and all keepalive packets will be dropped. Refer to Controlling IPX Type 20 Packet 
Forwarding
 on page 27-32 for help on using NetWare’s configurable parameters to change 
the frequency and number of keepalive/watchdog packets sent.
Enabling SPX Keepalive Spoofing
Follow the steps below to enable SPX Keepalive Spoofing.
1. Enter 
spxspoof
.
A screen similar to the following displays:
View the current spoofing status of all WAN routing services? (y or n) (n) :
Enter 
y
 if you do want to see the current SPX spoofing status. Enter 
n
 (or press 
<Enter>
) if 
you entered this command by mistake or if you don’t need to see the current status.
2. A screen similar to the following displays:
 Group           SPX Spoofing
----------
----------------------------
 3
Disabled
 4
Disabled
Enter Group (default: all WAN) :
Enter a Group number to proceed to enable SPX spoofing for that particular Group.
Or, press 
<Enter>
 to proceed to enable SPX spoofing for all WAN routing services.
3. The following prompt displays:
Enable Spoofing? (y or n) (n) :