Approach Styles (Link Layer More aggressive local remit than TCP 802. 11 protocols all do this. Receiver sends aCK after last bit of data Faster: bandwidth not wasted on wired links. Recover in a few milliseconds Possible adverse interactions with transport layer Interactions with tcp retransmission Large end-to-end round-trip time variation Recall TCP rto estimation. What does this do? FEC used in some networks (e.g, 802.11a) But does not work well with burst losses Wired link Wireless link ARQ/FEC Lecture25:11-302006 9Lecture 25:11-30-2006 9 Approach Styles (Link Layer) • More aggressive local rexmit than TCP • 802.11 protocols all do this. Receiver sends ACK after last bit of data. • Faster; Bandwidth not wasted on wired links. Recover in a few milliseconds. • Possible adverse interactions with transport layer • Interactions with TCP retransmission • Large end-to-end round-trip time variation • Recall TCP RTO estimation. What does this do? • FEC used in some networks (e.g., 802.11a) • But does not work well with burst losses Wired link Wireless link ARQ/FEC