TCP Masq

The tcp-masq is an add-on module to packet schedulers for bandwidth management at enterprise edges. tcp-masq regulates incoming TCP ACKs to achieve extra features such as flow isolation in one class, buffer requirement at the enterprise edges, and more accurate rate enforcement. tcp-masq implements the following three schemes:

(1)	TCP Rate Control (TCR), a TCP-aware add-on to schedulers patented by Packeteer, which exercises window-sizing and ack-pacing. TCR can accurately control bandwidth but is vulnerable to Internet losses while not robust to TCP sources. Window-sizing is currently prevalent among vendors without being fully explored.
(2)	PostAck, a TCP-aware add-on to schedulers, which migrates data queued in schedulers to reverse ack-buckets, minimizing buffer requirement up to 96%, as TCR can, but without vulnerability to Internet losses and is robust to TCP implementations.
(3)	PreAck, a helper function for rapid-rate recovery for TCR-applied flows, suitable for flows towards loss-constrained networks and achieves a performance gain of at least 45% during PreAck regardless of TCP versions. Detailed descriptions can be reached at Documentation pages.

Detailed descriptions can be found in the paper.

The tcp-masq runs over the ip-masq module present in the Linux kernel. The ip-masq performs network address translation (NAT) and belongs to the ip-chains (a firewall package). Thus tcp-masq can incorporate a rich set of policy-based classification rules from ip-chains. In addition, tcp-masq share its per-flow states with those in the NAT module, which employs a fast per-flow hash classifier. Furthermore, ip-masq is application-aware, which is required in PreAck, and supports protocols such as FTP, CUSeeMe, RealAudio, VdoLive.

Click the figure above to enlarge.

All results of this project can be reproduced through the open sources:
(1) tcp-masq: a Linux kernel patch, and
(2) wan-emu: a novel testbed for conducting switched LAN-to-WAN experiments with RTT/loss/jitter emulation.

News

A new benchmark report for bandwidth management devices is available at here. Test results in this report are verified by all the vendors.

Misc

If you have any comment or find bugs, please contact tcpmasq@yahoo.com.

Best view 800x600

Since Sept 2001, You're visitor No.

[ Stats ]