Implementing A Very Simple Protocol

Very Simple Virtual Circuit Protocol

Notes to the Writer

Goals

• Describe basic user procedure
• Begin to describe underlying architecture and components
• Talk about substrate concept

Sections

• xxx

Figures

• Application header format
• xxx

Links

• Overview Of The SPP Architecture

Versions

• 0
  • Protocol header chosen to work with iperf
  • Words (4 bytes) in header
    • Pkt ID (iperf UDP compatible)
    • Timestamp tv_sec
    • Timestamp tv_usec
    • VCI
    • Flow label (v1)
  • VCI is globally unique
  • 0.0
    • Minimalistic example
    • 1 router (R1), 2 hosts (H1, H2)
  • 0.1
    • Add monitoring daemon
  • 0.2
    • Like GEC 4, Part 1 but routes based on VCI
    • 2 routers (R1, R2), 6 hosts (H1-H6)
• 1
  • VCI can change during transit as part of pkt processing
  • Add Flow Label field

Configuring R1.0.0

• Use 2 physical interfaces from GEC4
• Use 2 hosts H1 and H2
• Replace R2 in GEC4 with H2
• FP
  • copt = 2
  • bw = 205 Mb/s
  • fltrs = xxx
  • qs = xxx
  • buffs = xxx
  • stats = fltrs
  • sram = xxx
• MIs
  • m1 (to H1)
    • bw = 100 Mb/s
    • ipaddr = 10.1.1.1
    • port = 20000
    • i.e., socket s1 = (10.1.1.1, 20000)
  • m2 (to H2)
    • bw = 100 Mb/s
    • ipaddr = 10.1.16.1
    • port = 20000
    • i.e., socket s2 = (10.1.16.1, 20000)
• Queues
  • q48 (LD): threshold = 100 pkts, bw = 1 Mb/s, mi = 0
  • q49 (EX): threshold = 100 pkts, bw = 1 Mb/s, mi = 0
  • q1: threshold = 1000 pkts, bw = m0.bw = 100 Mb/s, mi = 1
  • q2: threshold = 1000 pkts, bw = m1.bw = 100 mb/s, mi = 2
  • q0: not used
• VCIs
  • (R1, H1, H2) = (0, 1, 2) ==> Path (x,y) uses VCI 3*x+y
    • (H1, H2) uses VCI 5 = 3*1 + 2
    • Use 6 of 9 VCIs
  • Communication matrix
    • ( R1 (-, 1, 2), H1 (3, -, 5), H2 (6, 7, -) )
    • Unused VCIs: 0, 4, 8
• Filters (key = rxmi, vci)
  • f1 (R1 to H1): (rxmi, vci) = (0, 1), s = (10.1.1.1, 20000), qid = 1, sindx = 1 # substrate only
  • f2 (R1 to H2): (rxmi, vci) = (0, 2), s = (10.1.16.2, 20000), qid = 2, sindx = 2 # substrate only
  • f3 (H1 to R1): (rxmi, vci) = (1, 3), s = (10.1.16.1, 5555), qid = 0, sindx = 3
  • f4 (H1 to H2): (rxmi, vci) = (1, 5), s = (10.1.16.2, 20000), qid = 2, sindx = 4
  • f5 (H2 to R1): (rxmi, vci) = (2, 6), s = (10.1.16.1, 5555), qid = 0, sindx = 5
  • f6 (H2 to H1): (rxmi, vci) = (2, 7), s = (10.1.1.1, 20000), qid = 1, sindx = 6

User-space pkt

• Tunnel socket appears in UDP header
• VCI is first word of UDP payload
• Payload also has timestamp (for RTT and space-time diagram)

Substrate Implementation Concepts

• Physical interfaces
• Physical MIs
• Queues
• Filters
• Code option demultiplexor
• Parse, Lookup, Header Format

Slowpath Implementation

• Filters for local delivery
• User-space process to handle LD and EX traffic
  • Has VCI-MI Socket map; i.e., M : VCI --> MI Socket
  • Forwards pkt to socket M(pkt.VCI)
• Artifacts
  • Tunnel-aware sender and receiver
  • User-space process to handle monitoring data
  • spp-config-sp-vsvc-XXX.sh (slowpath) configuration scripts

Fastpath Implementation

• Requires mods to Parse and Header Format
• Uses generic Lookup
• Additional artifacts
  • spp-config-fp-vsvc-XXX.sh (fastpath) configuration scripts
  • Monitoring

Interesting Demo

• xxx