Instruction manual

Chapter 2 Installation, Configuration and Management
NetScaler 9000 Series Installation and Configuration Guide - Volume 1 2-79
NSICG60_DEC04
Table 4-1 Conditions and Behavior of the NetScaler System on Receipt of a
PMTU related ICMP Error
2.7.2 Behavior of the NetScaler System in Transparent Mode
In the Transparent mode, if the server sets the DF bit and sends a datagram, if
the Path MTU is smaller than the size of the datagram, the ICMP error is
received by the NetScaler system. The following table lists out the conditions
and the expected behavior of the NetScaler system on receipt of a PMTU
related ICMP error message:
No. Condition
Behavior of the NetScaler
System
1 For client connections, the
NetScaler system uses an MSS
of 1460 bytes. The MSS of the
packets sent to the client is
minimum of 1460 bytes as
received from the client. While
routing the packet if the network
contains a router that fragments
the packet into multiple
datagrams because of MTU
mismatches, an ICMP error is
sent by the router.
The NetScaler system should
parse the ICMP error and
estimate a lower MTU
appropriately for the path to that
particular client. In this case, the
ICMP error will not be passed to
the server. The MTU database
will be updated with the lower
MTU. All new connections use
the lowered MTU value from the
database.