While having an increased MTU across your WAN can improve throughout greatly, I would suggest tuning your TCP stack for a "Long Fat Pipe", as many operating systems are not designed to work well with high-throughput, high-latency links.
There are some good tips here: http://fasterdata.es.net/ Cheers, jof On Sep 30, 2010 10:38 PM, "Harris Hui" <[email protected]> wrote: Dear all, We had subscribed a private line circuit between 2 different data center for Data Backup and replication. The bandwidth of the private line is 100Mbps. According to the provider, The Circuit is Built across their Network as 2 STS1's or High Speed DS3's which equals 100meg. Their GE port setting as follows. MTU Size - 9600 Auto Negotiation - OFF Remote Client Fail - Disabled. The private circuit is connected directly to the fiber module of our J6350 Services router at each Data Center. The Circuit is up and running but when we perform some TCP throughput test, we only get ~3Mbps for a Single TCP session with iPerf and the latency between two data center across the private circuit is ~80ms. I am trying to configure our J6350 fiber interface to MTU 9192 to get a better TCP throughput. However, I can only able to configure the MTU size below 1500, when I configure the MTU to 9192 and commit the changes, it still shows MTU 1500 on the physical interface. Do you have any experience on using Jumbo frame MTU size on the J6350? We are also running OSPF across the private circuit, is JUNOS support "OSPF ignore-mtu" like cisco? Please advise. Fiber module ================================================ FPC 3 REV 18 750-013599 AAAH7361 FPC PIC 0 1x GE SFP Xcvr 0 REV 02 740-011614 PG336CS SFP-LX10 show interfaces ge-3/0/0 speed 1g; mtu 1400; link-mode full-duplex; gigether-options { no-auto-negotiation; } unit 0 { family inet { address xxx.xxx.xxx.253/30; } } har...@j6350# run show interfaces ge-3/0/0 Physical interface: ge-3/0/0, Enabled, Physical link is Up Interface index: 152, SNMP ifIndex: 184 Link-level type: Ethernet, MTU: 1400, Speed: 1000mbps, BPDU Error: None, MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Disabled, Remote fault: Online Device flags : Present Running Interface flags: SNMP-Traps Internal: 0x4000 Link flags : None CoS queues : 8 supported, 8 maximum usable queues Current address: b0:c6:9a:87:35:36, Hardware address: b0:c6:9a:87:35:36 Last flapped : 2010-09-27 02:32:24 UTC (4d 02:29 ago) Input rate : 0 bps (0 pps) Output rate : 0 bps (0 pps) Active alarms : None Active defects : None show interfaces ge-3/0/0 speed 1g; mtu 9192; link-mode full-duplex; gigether-options { no-auto-negotiation; } unit 0 { family inet { address xxx.xxx.xxx.253/30; } } run show interfaces ge-3/0/0 Physical interface: ge-3/0/0, Enabled, Physical link is Up Interface index: 152, SNMP ifIndex: 184 Link-level type: Ethernet, MTU: 1514, Speed: 1000mbps, BPDU Error: None, MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Disabled, Remote fault: Online Device flags : Present Running Interface flags: SNMP-Traps Internal: 0x4000 Link flags : None CoS queues : 8 supported, 8 maximum usable queues Current address: b0:c6:9a:87:35:36, Hardware address: b0:c6:9a:87:35:36 Last flapped : 2010-09-27 02:32:24 UTC (4d 02:35 ago) Input rate : 0 bps (0 pps) Output rate : 1192 bps (2 pps) Active alarms : None Active defects : None Thanks Harris _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
