Release Note для Cisco Cisco Packet Data Gateway (PDG)
SGSN Changes in Release 15.0
SGSN Enhancements for June 6, 2014 ▀
Cisco ASR 5x00 Release Change Reference ▄
477
CSCuj62285 - IP tcp mss settings on sgsn
Feature Changes
Making TCP MSS Configurable
Previous Behavior: The SGSN transparently passed the maximum segment size (MSS for TCP uplink/downlink
traffic) in TCP SYN (and SYN-ACK) messages between UE and the server. In cases where the MSS value exchanged
between UE and server is 1460 or more, with the addition of the GTP header, the packets often would be fragmented,
which resulted in packets being dropped by network nodes that could not handle fragmentation.
traffic) in TCP SYN (and SYN-ACK) messages between UE and the server. In cases where the MSS value exchanged
between UE and server is 1460 or more, with the addition of the GTP header, the packets often would be fragmented,
which resulted in packets being dropped by network nodes that could not handle fragmentation.
New Behavior: To avoid fragmentation, the SGSN can now be configured to modify/overwrite the TCP MSS value
exchanged between the UE and the server (for both 2G and 3G uplink/downlink traffic) if the requested value is more
than the SGSN's locally configured value.
exchanged between the UE and the server (for both 2G and 3G uplink/downlink traffic) if the requested value is more
than the SGSN's locally configured value.
Command Changes
tcp-maximum-segment-size
This new command in the Call Control Profile configuration mode enables the operator to define a maximum segment
size (MSS), that will be used to overwrite received TCP MSS values in uplink/downlink packets between UE to the
server.
size (MSS), that will be used to overwrite received TCP MSS values in uplink/downlink packets between UE to the
server.
configure
call-control-profile profile_name
tcp-maximum-segment-size size
remove tcp-maximum-segment-size
end
Notes:
size
- is the maximum number of octets for a segment, value range is 1 to 1460.
remove
- as part of the command, returns the MSS to the SGSN’s default of 1460 octets.
An additional Yes/No prompt is included due to the high impact of the MSS configuration.
CSCul70235 - 'show sgsn sessmgr all ptmsi statistics' displays NRI Values
incorrectly
Feature Changes
Clarify Display Information