Rough Outline for a Intra-Portal Protocol
Version 01
Stephen Haddock
July 17, 2012
1
LACP in a Nutshell
• Each Port on a System advertises:
1.
A System ID
•
2.
A Key
•
3.
The same System ID value is used for all Ports on a System.
The Key is an indication of aggregation capability. Ports that can be
aggregated advertise the same Key value.
A Port ID
•
The Port ID is included to handle some special cases. It is not important for
a high level understanding of basic LACP concepts.
• LACP Selection Logic will form an aggregation between
any ports that:
1.
2.
Advertise the same System ID and the same Key (called the
Actor_System and Actor_Key), and
Receive advertisements containing the same System ID and the
same Key (called the Partner_System and Partner_Key)
2
Two Systems without Distributed Aggregation
System A
Port
Port
Port
System B
Port
Port
Each Port on System A advertises:
1. Actor_System = A
2. Actor_Key = Ax
Where Ax may be the same value
on some or all of the ports, or
may be a different value on
different ports.
Port
Port
Port
Port
Port
Each Port on System B advertises:
1. Actor_System = B
2. Actor_Key = Bx
Where Bx may be the same value
on some or all of the ports, or
may be a different value on
different ports.
3
Two Systems with Distributed Aggregation
System A
Port
Port
System B
Port
Port
Port
Port
(possible) Network Link
Intra-Portal Link (could be virtual)
Network Link
Gateway
Link
(virtual)
Emulated System C
Port
Port
Each Network Port on System A advertises:
1. Actor_System = A
2. Actor_Key = Ax
Port
Port
Port
Port
Port
Port
Network Link
Gateway
Link
(virtual)
Each Network Port on System B advertises:
1. Actor_System = B
2. Actor_Key = Bx
Each (non Gateway) Port on System C advertises:
1. Actor_System = C
2. Actor_Key = Cn
Where Cn is the same value on all of the ports.
4
Intra-Portal Protocol
Creating and Maintaining a Distributed Aggregation requires:
• State machines in System A and System B (the “real”
systems) to control the transitions between the state
without distributed aggregation and the state with
distributed aggregation.
• A protocol that
1.
2.
3.
Determines the System ID and Key values for the Emulated
System C.
Coordinates the Selection Logic for the Emulated System C.
Coordinates the distributed aggregation state machines in each of
the “real” systems.
5
Configuration versus Discovery
• LACP designed to allow minimal configuration and
maximal discovery:
– A default configuration is all ports advertise the same key value.
– LACP will then discover all groups of ports connecting the same
pair of systems and automatically aggregate them.
• The Intra-Portal Protocol could conceivably follow the
same philosophy:
1.
2.
3.
•
Advertise ability to do distributed aggregation on all ports.
Form an Intra-Portal Link to any connected system that is also
capable of distributed aggregation, and create an emulate system
between them.
Use LACP (possibly with enhancements) to discover links that
could form a distributed aggregation and “move” those ports to
the emulated system.
This is quite ambitious!
6
A less ambitious starting point
1. Configure the port(s) that are expected to form IntraPortal Links.
–
Use protocol advertisements on those ports to verify that the
other system also expects these to form Intra-Portal Links, and to
agree on Emulated System parameters (System ID, Key value,
Port IDs).
2. Configure which port(s) are expected to be “moved” to
the Emulated System.
–
–
Once the Intra-Portal Link is active and Emulated System
parameters agreed, use LACP to advertise the Emulated System
parameters these ports.
Intra-Portal Protocol coordinates the Selection Logic of the
Emulated System to form the distributed aggregation.
7
Rough Distributed Aggregation State Machine
Begin
SINGLE
•LACP advertises “real” system
parameters on all ports.
•Send Intra-Portal Protocol
advertisements (candidate
Emulated System parameters)
on potential Intra-Portal Port.
All communication
with spouse lost
ESTRANGED
•LACP advertises Emulated
System parameters on Emulated
System ports.
•Send Intra-Portal Protocol
advertisements on Intra-Portal
Port and alternate paths.
•Maintain Distributed
Aggregation
IPPort Operational &
IPProtocol
Advertisements
received
All communication
with spouse lost
All communication
with spouse lost
IPPort Operational &
IPProtocol
Advertisements
received
IPPort not Operational
but communication
through other paths
possible
BETROTHED
•LACP advertises “real” system
parameters on all ports.
•Send Intra-Portal Protocol
advertisements on Intra-Portal
Port.
Not in
sync
In sync (Emulated
System parameters
agreed)
MARRIED
•LACP advertises Emulated
System parameters on Emulated
System ports.
•Send Intra-Portal Protocol
advertisements on Intra-Portal
Port (and alternate paths?).
•Create Distributed
Aggregation.
8
Intra-Portal Protocol Advertisements
• Ethertype
• Maybe use Slow Protocols Ethertype with new sub-type
• Maybe use new Ethertype (without chatter limits)
• Modeled after LACP advertisements
– Contains Actor parameters
• Actor_System, Actor_Emulated_System, Actor_Distributed_Key, Actor_State
– Contains copies of parameters received from Spouse
• Spouse_System, Spouse_Emulated_System, Spouse_Distributed_Key, State
– In sync when the Spouse_* parameters in received advertisements
match the Actor_* parameters in transmitted advertisements.
• The agreed Emulated_System identifier is the numerically lower of that
proposed by the Actor or the Spouse.
• The agreed Distributed_Key is the value associated with the agreed
Emulated_System identifier.
• May contain other TLVs in some or all advertisements for
coordinating gateway selection, link selection, etc.
9
Obviously needs further refinement
10
Thank You
.
11