Barricade SMC7008ABR, Руководство по установке

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Part H
– Adjusting MTU Value
MTU, Partial Loss of Internet Connection, and Performance
o
MTU (Maximum Transmission Unit) is the largest packet a network
device transmits. The best MTU setting for equipment is often just the
default value. MTU is sometimes presented as something that can be
easily changed to improve performance, but in practice this may cause
problems.
You need to follow this procedure in order to prevent problems
with the VPN connection. This will manifest itself as severe performance
problems such as chronic disconnects
.
o
Setting MTU size is a process of trial-and-error: start with the
maximum value of 1500, then reduce the size until the problem goes
away.
In order to find the optimum size for the MTU setting you will need to utilize the
extended portions of the PING command. (The parameters are case sensitive!)
PING –f –l 1500 fpnet.galileo.com
-f Set Don’t Fragment flag in packet
-l size Send buffer size (lowercase L)
If you have a problem with the packet size the following message will be returned:
Packet needs to be fragmented but DF set.
Reduce the size of the send buffer until the reply message comes back normally.
Reply from 12.17.202.11: bytes=1500 time=36ms TTL=59