Cisco路由器：增加LLC计时器的消息；建议
问题描述
我有一个带有dlsw的Cisco 4500路由器，我收到一个增加LLC计时器的消息。性能很慢。
我是否应当增加llc2 t1-time?
配置信息
操作系统 - HP-UX
版本 -
硬件系统 - HP9000
系列 -
解决方法
是的，错误信息指出T1计时器(ack计时器)弹出，增加ack计时器(T1)应当降低故障的可能性。
使用SRB超慢串行链接的LLC计时器建议
下面的建议适用于远程源路由桥接环境主机上的计时器设置：
T1 - 1到2秒是正常的缺省值，它应当大于帧可能在发送结点、网络和接收结点内的总往返延迟时间。在速度比较慢的广域网链接下(
Ti - 建议这个值设置为至少T1计时器的10倍，式一下30左右的值，以获得最佳效果。通常你不必修改这个设置。Ti截止时发送RR，然后在RR启动T1计时器。
T2 - 这个值正常情况下应当在80与256毫秒之间，必须至少小于T1。一般不对此进行调整，如果它太长，可能会影响响应时间，导致不必要的重发。.
注释
-----
在本地应答的环境中，通常不必调整T1、Ti或T2计时器，除非一个帧遍历无数的本地桥接器或路由器。
T1 = 一个设备等待对传送帧的答复的时间。
Ti = 不活动超时。这就象一个会话保持计时器，如果一个链接站在这个计时器定义的时间长度内，没有收到来自与之有会话的一个设备的信息这个链接站就会发送一个RR，看一看设备是否仍然可达。
T2 = 应答延迟计时器。这个值定义在收到数据包之后、做出响应前的最大时间。
上述信息摘自http://www.cisco.com/。
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.........following with all English text ....
[A5346115/TRAK-ACTIVE/English] A5346115
Cisco Router: Message to increase LLC timers; recommendations
Problem Description
I have a Cisco 4500 router with dlsw. I am receiving a message
to increase LLC timers. Performance is slow.
Should I increase the llc2 t1-time?
Configuration Info
Operating System - HP-UX
Version -
Hardware System - HP9000
Series -
Solution
Yes, the error indicates is that the T1 timer (ack timer) popped.
Increasing the ack timers (T1) should decrease the likelihood of a
failure.
LLC Timer Recommendations Using SRB Over Slow Serial Links
----------------------------------------------------------
The following recommendations are for timer settings on the hosts in
a remote source route bridged environment:
T1 - 1 to 2 seconds is the normal default. This should be greater than
the total round trip delay time that the frame might encounter within
the sending node, the network, and the receiving node. On slower WAN
links (
3 to 3.5 seconds to reduce retransmissions and connection timeouts.
Ti - This value is recommended as being at least 10 times the T1 timer.
Try values around 30 for best results. You usually don't need to change
this setting. Ti expiration causes an RR to be transmitted, and then a
T1 timer is started against the RR.
T2 - This normally should be between 80 and 256 msec, and must be less
than T1. This is not generally tuned. If it is too long, it could hurt
response times and cause unnecessary retransmissions.
Notes
-----
In a locally acknowledged environment, it is not usually necessary to
tune T1, Ti or T2 timers unless a frame is traversing numerous local
bridges or routers.
T1 = how long a device waits for a reply to a transmitted frame.
Ti = inactivity timeout. This is like a session keep alive timer.
If a link station hasn't heard from a device with which it has a session
for the length of time defined by this timer, the link station will send
an RR to see if the device is still reachable.
T2 = acknowledgment delay timer. This value defines the maximum time
after receiving a packet before responding.
The above information is from http://www.cisco.com/.
