AVB协议培训简明教程3- SRP

R/D
B6
D D/R
TA TA/LR
O L2
O L1
T
Talker Station
L
Listener Station
Other O Station
B Bridge
6
SRP Network showing Bandwidth Loss
TA/LRF R/D B2 D TA
B1 D/R
D/R
O
R/D D
MSRP (35.1)
Multiple Stream Registration Protocol
MVRP (11)
Multiple VLAN Registration Protocol
MAP (35.2.4)
MSRP Attribute Propagation
MRP (10)
Multiple Registration Protocol
fdb (8.8.9)
Filtering database
Above references are to clauses in 802.1Q
Note the narrow connection from the switch to the CPU! Bandwidth on this path is an issue.
Listener
– Receives Talker Advertise – Join VLAN via MVRP: VLAN-ID – Attach to Stream via MSRP: STREAMID
Talker
– Receives Listener Ready (Attach) – Begin streaming data
4
SRP Network showing Listener Ready (LR)
LR B1 R D LR
O T
D B2
R
O
LR
D
LR
B3 R
R
LR
D B4 R
LR O
L1
D B5 R O LR
D B6
R
LR O
L2
T
Talker Station
L
Listener Station
Other O Station
B Bridge
5
SRP Network showing both TA and LR
TA/LR
R/D B2 D TAB1 D/RD/ROR/D D
TA TA/LR
TA/LR
R/D
R/D B5 D
TA/LR
D/R
TA
O T
B3 D/R
D/R
O TA/LR
TA/LR
R/D
B4
D/R D
TA TA/LR
Stream data
– A Talker-to-Listener connection often 1722 based – Flows through the fast path of the Bridge based on Forwarding tables – Consumes no CPU resources
13
SRP Data Stream
MAD
MAD
MAD
SRP
CPU MSRP MVRP MAP MRP
switching fabric
fast path
fdb
fdb
fdb
Data Stream enters from Talker side on port 1 The StreamDA is not a special MAC DA so it is not sent to CPU Switching fabric finds StreamDA in fdb for port 3 and forwards packet there Packet will be transmitted as soon as Credit Based Shaper allows
10
Simplified „Q‟ Bridge Model
MAD
MAD
MAD
SRP
CPU MSRP MVRP MAP MRP
switching fabric
fast path
fdb
fdb
fdb
1
2
3
MAD (10.2)
MRP Attribute Declaration
SRP (35)
Stream Reservation Protocol
1
2
3
12
SRP Listener Ready
MAD
MAD
MAD
SRP
CPU MSRP MVRP MAP MRP
switching fabric
fast path
fdb
fdb
fdb
1
2
3
Listener Ready (LR) enters on port 3 Switching fabric recognizes special MAC DA (01:80:c2:00:00:0e) and passes packet to CPU CPU recognizes Ether Type (0x22ea) and passes to SRP/MSRP MSRP consumes packet and updates MAD database MAP associates LR with TA and creates a reservation by updating Credit Based Shaper on port 3, and putting StreamDA in port 3 Forwarding database (fdb) MSRP generates a new LR and transmits it out port 1 (where TA was registered)
T
Talker Station
L
Listener Station
Other O Station
B Bridge
7
SRP Overview
Establish the domain (VID and SR Class Priorities) Talker
– Advertise Stream: STREAMID, STREAMDA, VLAN-ID, SR CLASS, RANK, ETC.
TA B1 D RD
TA TA
O T
R B2 D TA
D
O
TA
R
TA
B3 D
D
TA
R
B4
DD
TA
TA
O L1
T
Talker Station
R B5 D TA
D
TA
O
L
Listener Station
Other O Station
R
B6
DD
TA
TA
B Bridge
O L2
Note: D = Declaration from transmitting device R = Registration on receiving device
Listener Ready
Talker Advertise (VID=5, Prio=4) MVRP Membership Join (VID=5)
Listener Ready
1722/1733 Data Stream (VID=5, Prio=4)
1722/1733 Data Stream (VID=5, Prio=4)
9
Stream Control vs Stream Data
It is important to understand the subtleties of advertising and reserving streams vs. the resultant stream data flow.
Stream control
1
SRP Related Specification
MRP – Multiple Registration Protocol (802.1ak-2007) MRP Corrigendum – Bug fixes to MRP SRP – Stream Reservation Protocol (802.1Qat) “Q” – Media Access Control (MAC) Bridges (802.1Q-2011)
TA TA/LRF
TA/LRF
R/D B5 D
R/D
TA/LAF
D/R
TA
O T
B3 D/R
D/R
O TF/LAF
TA/LR
R/D
B4
D/R D
TA TA/LR
Assuming this link loses available bandwidth
R/D
B6
D D/R
TF TF/LAF
O L2
O L1
O
Other O Station
B Bridge
O L2
Network representational concept borrowed from Michael Johas Teener with permission
3
SRP Network showing Talker Advertise (TA)
11
SRP Talker Advertise
MAD
MAD
MAD
`
SRP
CPU MSRP MVRP MAP MRP
switching fabric
fast path
fdb
fdb
fdb
Talker Advertise (TA) enters on port 1 Switching fabric recognizes special MAC DA (01:80:c2:00:00:0e) and passes packet to CPU CPU recognizes Ether Type (0x22ea) and passes packet to SRP/MSRP MSRP consumes packet and updates MAD database by registering TA on port 1 MSRP generates two new TA packets and transmits them on port 2 and port 3
IEEE Get Program – free download of published 802.1 standards
2
SRP Network with a Talker and two Listeners
B1 O
T
B2 O
B3
B4 O
L1
B5 B6
T
Talker Station
L
Listener Station
Subsequent Listener(s) attach
– Bridges proxy for Talker Advertise – Talker doesn’t know about these Listeners
8
SRP Domain Negotiations
Talker
SRP Domain (VID=2, Prio=3) SRP Domain (VID=5, Prio=4) SRP Domain (VID=5, Prio=4)
– A conversation between link partners that is regenerated at each Bridge – Consumes Bridge resources such as CPU cycles and memory – Updates Filtering/Forwarding tables and the Credit-based Shaper
Bridge
SRP Domain (VID=2, Prio=3) SRP Domain (VID=5, Prio=4) SRP Domain (VID=5, Prio=4)
Listener
Talker Advertise (VID=5, Prio=4) MVRP Membership Join (VID=5)
What is SRP?
A Bridge and End Station based protocol to:
– Establish AVB “cloud” boundaries to exclude non-AVB devices – Protect AVB “cloud” from illegal use of SR Class priorities – A single protocol supported by wired, wireless, MoCA, G.hn, etc. – Provide low latency “stream” path(s) through network – Describe stream resource requirements to a bridged network – Update Bridge forward/filter tables for directed multicast traffic – Update Credit Based Shaper for stream bandwidth requirements – Regulate bandwidth hogs that try to exceed reservations – Establish VLANs between Talker and Listener(s)