According to http://www.mynetwatchman.com/kb/adsl/pppoemtu.htm , the optimal MTU for PPPoE connections is 1454. Anything above that adds an extra ATM cell with padding bytes for each frame you send and receive.
I'm not sure what to make of the 5808-byte receive window. What are the contents of /proc/sys/net/core/[rw]mem*? How does the speed test at dslreports.com compare?
Bennett, Joe wrote:
Was playing around on speedguide.net and ran their analysis tool for MTU RWN etc. My WinXP box showed exactly what I expected in the report. My Suse 9.0 box showed the report below. Any ides on the RWIN of 5808? Ran two different browers with no change and followed there recommendation here: http://www.speedguide.net/read_articles.php?id=121 on adding these commands into boot.local. No dice...
I'm a bit skeptical since my speed tests with SBC show the bandwidth of my DSL connection. I would have figured that 5808 would create so many acks that speed would be sacrificed...????
Ideas??
TCP options string = 020405ac0101040201030300 MTU = 1492 MTU is optimized for PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput. MSS = 1452 MSS is optimized for PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput. Default Receive Window (RWIN) = 5808 RWIN Scaling (RFC1323) = 0 bits Unscaled Receive Window = 5808
RWIN is a multiple of MSS Other values for RWIN that might work well with your current MTU/MSS: 511104 (MSS x 44 * scale factor of 8) 255552 (MSS x 44 * scale factor of 4) 127776 (MSS x 44 * scale factor of 2) 63888 (MSS x 44) bandwidth * delay product (Note this is not a speed test):
Your RcvWindow limits you to: 232.32 kbps (29.04 KBytes/s) @ 200ms Your RcvWindow limits you to: 92.928 kbps (11.616 KBytes/s) @ 500ms Consider increasing your RWIN value to optimize TCP/IP for broadband. MTU Discovery (RFC1191) = ON Time to live left = 52 hops
TTL value is ok. Timestamps (RFC1323) = OFF Selective Acknowledgements (RFC2018) = ON IP type of service field (RFC1349) = 00000000 _______________________________________________ Kclug mailing list [email protected] http://kclug.org/mailman/listinfo/kclug