Cisco 9134 - MDS Multilayer Fabric Switch User Manual

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20-48
Cisco MDS 9000 Family Troubleshooting Guide, Release 3.x
OL-9285-05
Chapter 20 Troubleshooting IP Storage Services
iSCSI TCP Performance Issues
Advertized window: Current: 61 KB, Maximum: 62 KB, Scale: 0
Peer receive window: Current: 63 KB, Maximum: 63 KB, Scale: 0
Congestion window: Current: 63 KB
Target node: iqn.com.domainname.IPS-TEST.02-08.gw.2200002037c5260a
Statistics:
PDU: Command: 13, Response: 13
Bytes: TX: 1344, RX: 0
Number of connection: 1
TCP parameters
Connection Local 10.1.29.100:3260, Remote 10.1.29.101:1048
Path MTU 1500 bytes
Current retransmission timeout is 300 ms
Round trip time: Smoothed 165 ms, Variance: 35
Advertized window: Current: 61 KB, Maximum: 62 KB, Scale: 0
Peer receive window: Current: 63 KB, Maximum: 63 KB, Scale: 0
Congestion window: Current: 63 KB
Target node: iqn.com.domainname.IPS-TEST.02-08.gw.2200002037c5260a
Statistics:
PDU: Command: 13, Response: 13
Bytes: TX: 1344, RX: 0
Number of connection: 1
TCP parameters
Connection Local 10.1.29.100:3260, Remote 10.1.29.101:1048
Path MTU 1500 bytes
Current retransmission timeout is 300 ms
Round trip time: Smoothed 165 ms, Variance: 35
Advertized window: Current: 61 KB, Maximum: 62 KB, Scale: 0
Peer receive window: Current: 63 KB, Maximum: 63 KB, Scale: 0
Congestion window: Current: 63 KB
Target node: iqn.com.domainname.IPS-TEST.02-08.gw.2200002037c5260a
Statistics:
PDU: Command: 13, Response: 13
Bytes: TX: 1344, RX: 0
Number of connection: 1
TCP parameters
Connection Local 10.1.29.100:3260, Remote 10.1.29.101:1048
Path MTU 1500 bytes
Current retransmission timeout is 300 ms
Round trip time: Smoothed 165 ms, Variance: 35
Advertized window: Current: 61 KB, Maximum: 62 KB, Scale: 0
Peer receive window: Current: 63 KB, Maximum: 63 KB, Scale: 0
Congestion window: Current: 63 KB
iSCSI TCP Performance Issues
Generally there are two segments that effect the iSCSI performance. First is the Fibre Channel side flow
control mechanism, buffer to buffer credits (BB_credits), Fibre Channel maximum frame size. Second
is the TCP/IP side segment.
As in all TCP/IP-related throughput issues, the most important criteria are the Receive/Send Window
Sizes on both TCP endpoints, RTT (round trip time), actual available bandwidth between the TCP peers,
the MSS (maximum segment size), and the support for higher MTUs between the peers.

Cisco 9134 - MDS Multilayer Fabric Switch Specifications

General

Brand	Cisco
Model	9134 - MDS Multilayer Fabric Switch
Category	Switch
Language	English