110 likes | 274 Views
Fibre Channel Over MPLS. IETF/T.11 interworking draft-ietf-pwe3-fc-encap-02.txt Tuesday, November 7th, 2006 Moran Roth – Corrigent Ronen Solomon – Corrigent Munefumi Tsurusawa – KDDI LABs. Topics. New draft draft-ietf-pwe3-fc-encap- 02 .txt Reliable congestion control
E N D
Fibre Channel Over MPLS IETF/T.11 interworking draft-ietf-pwe3-fc-encap-02.txt Tuesday, November 7th, 2006 Moran Roth – Corrigent Ronen Solomon – Corrigent Munefumi Tsurusawa – KDDI LABs
Topics • New draft draft-ietf-pwe3-fc-encap-02.txt • Reliable congestion control • Encapsulation format • Signaling of FC PW
FC PW congestion control - Rate control • Based on TFRC (RFC 3448) • CIR and EIR are configured per FC service and FCoMPLS frames are marked accordingly. • Throughout [Bytes/Sec] – actual sending rate is a function of loss event rate and round trip time (RTT). • Loss event – one or more frames dropped within a single LAPB window
FC PW congestion control - Selective retransmission • Based on LAPB (FC-BB-3 standard) • Reliable protocol • Sequencing and re-sequencing mechanism • Acknowledgments - to the sender • Frame loss retransmission
FC PW congestion control - Selective retransmission (cont.) • LAPB message type • I-frame (information frame). • Carries the actual FC information ( data and control) • Includes N(S) and N(R) counters for sequencing and acknowledgment . • S-frame (supervisory frame). • RR ( Receiver Ready) – includes the N(R) counter to acknowledge sender frames. • RNR ( Receiver Not Ready) – includes the N(R) counter to acknowledge sender frames and stop the transmitter. • SREJ (Selective Reject) – indicates sequence numbers of dropped frames to feed the transmitter. • Recommended to send S-frames as high-priority (EF).
FC PW congestion control - Selective retransmission (cont.) • Retransmission protocol mechanism parameters • T1-Poll Timeout • T2 -Response Timeout • K – window size • N2 - Poll Retries • Protocol mechanisms ‘Poll’ and ‘final’ indication bits
L2 header MPLS label PW label FC PW Control word (mandatory} LAPB header FC frame FC frame L2 CRC FC PW encapsulation
FC PW control word • Control word is REQUIRED • A – address bit part of the LAPB protocol indication • FRG – fragmentation is not supported • Length – short frame indication used (minimum 40bytes FC frame) • Sequence number – not used ( LAPB sequencing)
Signaling of FC PW • PW type in FEC = FcPort • Control word is REQUIRED - C-bit in FEC must be set. • Interface parameters • Four new Sub TLV – TBA • Length of each 4 bytes • Type = T1 , T2 ,N2 , K • Both PE’s should agree on these value for succesful PW setup.
Summary • Assign new PW Type “Fibre Channel port mode” • Assign parameter ID for interface parameters SUB TLV • Draft-02 is ready for cross area review ?