Re: [Forces-protocol] FE Protocol LFB, FE LFB, CE LFB (draft sections) to review.

[Robert Haas <[e-mail]>]

All,
Attached is the text updated according to Weiming's comments.

Regards,
-Robert


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We can remove sections 3.3.2 and 3.3.3, and replace them with a single 
section that provides an overview of what these "special LFBs":

New section 3.3.2:

Whereas four key PL messages have a specific type assigned (Association 
Setup, Response, and Teardown, as well as Heartbeat) mostly for 
simplicity and monitoring reasons, all other PL messages follow the LFB 
structure as this provides more flexibility for future enhancements. In 
addition, this shows how the ForCES protocol itself can be controlled by 
the very same type of structures (LFBs) as it uses to control functions 
such as IP forwarding, filtering, etc.

To achieve this, the following LFBs are used: FE Protocol LFB, FE LFB, 
and CE LFB. These LFBs are detailed in Section XXX. An short description 
is provided here:

The FE Protocol LFB is a logical entity in each FE that is used to 
control the ForCES protocol. The CE operates on this LFB to subscribe or 
unsubscribe to Heartbeat messages, define the Heartbeat interval, or 
discover which ForCES protocol version and which TMLs the FE supports. 
The FE Protocol LFB also contains the various ForCES ID to be used: 
unicast IDs and table of the PL multicast IDs the FE must be listening to.
[TBD: I don't think we need a CE Protocol LFB]

The FE LFB (referred to as "FE attributes" in the model draft) should 
not be confused with the FE Protocol Object. The FE LFB is a logical 
entity in each FE and contains attributes relative to the FE itself, and 
not to the operation of the ForCES protocol between the CE and the FE. 
Such attributes can be FEState (refer to model draft), vendor, etc. The 
FE LFB contains in particular an table that maps a virtual LFB Instance 
ID to one or more Instance IDs of LFBs in the FE.

The CE LFB is the counterpart of the FE LFB. The CE LFB is a logical 
entity in each CE and contains attributes relative to the CE itself, and 
not to the operation of the ForCES protocol between the CE and the FE. 
This LFB can be used to convey event notifications from a CE to FEs. 
Some events may be sent by the CE without prior subscription by the FEs.

------------------------------------------------------------------------------------------------------------------- 

The following section should be inserted just before the "Protocol 
Messages" section. It provides the detail (in english, not xml) of the 
LFBs.

Chapter X: FE, CE, and Protocol LFBs.

The FE LFB, CE LFB, and FE Protocol LFB are used to control the 
operation of the ForCES protocol and interact with FEs and CEs.
Although these LFBs have the same form and interface as other LFBs, they 
are special in many respects: they have fixed well-known LFB Class and 
Instance IDs. They are statically defined (no dynamic instantiation 
allowed) and their status cannot be changed by the protocol: any 
operation to change the state of such LFBs (for instance, in order to 
disable the LFB) must result in an error. Moreover, these LFBs must 
exist before the first ForCES message can be sent or received. All 
attributes in these LFBs must have pre-defined default values. Finally, 
these LFBs do not have input nor output ports and do not integrate into 
the intra-FE LFB topology.

Section X.1 FE Protocol LFB

The FE Protocol LFB is a logical entity in each FE that is used to 
control the ForCES protocol. The FE Protocol LFB Class ID is assigned 
the value 0x1. The FE LFB Instance ID is assigned the value 0x1. There 
must always be one and only one instance of the FE Protocol LFB in an 
FE. The values of the attributes in the FE Protocol LFB have pre-defined 
default values that are specified here. Unless explicit changes are made 
to these values using Config messages from the CE, these default values 
MUST be used for the operation of the protocol.

The FE Protocol Object consists of the following elements:

FE Protocol events that can be subscribed/unsubscribed:
   FE heartbeat
   FE TML events (TBD)
FE Protocol capabilities (read-only):
   Supported ForCES protocol version(s) by the FE
   Supported ForCES FE model(s) by the FE
   Some TML capability description(s)
 FE Protocol attributes (can be read and set):
   Current version of the ForCES protocol
   Current version of the FE model
   FE unicast ID
   FE multicast ID(s) (list)
   Association Expiry Timer
   Heartbeat Interval
   Primary CE
   FE failover and restart policy
   CE failover and restart policy [XXX: what is the diff with FE failover ?]
 
[TBD: define default values for each attribute if applicable]

Section X.2

The FE LFB is a logical entity in each FE and contains attributes 
relative to the FE itself, and not to the operation of the ForCES 
protocol.  The FE LFB Class ID is assigned the value 0x2. The FE LFB 
Instance ID is assigned the value 0x1. There must always be one and only 
one instance of the FE LFB in an FE.

The FE LFB consists of the following elements:
FE Events:
   FEAllEvents (subscribing to this corresponds to subscribing to all 
events below)
   FEStatusChange (events that signal FE Up/Down/Active/Inactive/Failover)
   FE DoS alert
   FE capability change
 FE attributes:
   FEStatusChange (to set the FE in Active, Inactive, or Shutdown mode 
[Note: this replaces the State Maintenance messages])
   MIID table (a list of virtual LFB Instance IDs that map to a list of 
Instance IDs of LFBs in that FE [Refer to Zsolt's note])
   FE Behavior Exp. Timer
   HA Mode
   FE DoS protection policy
   [the attributes below were previously under Query message]
   Inter-FE topology
   Intra-FE topology


Section X.3

The CE LFB is a logical entity in each CE and contains attributes 
relative to the CE itself, and not to the operation of the ForCES protocol.

The CE LFB consists of the following elements:
 CE Events:
   CEAllEvents (subscribing to this corresponds to subscribing to all 
events below) [Do we want to allow an FE to explicitely subscribe to CE 
events ?]
   CEStatusChange (events that signal CE 
Up/Down/Active/Inactive/Failover)  [Such events do not necessarily need 
to be subscribed to, they can fire even without subscription and inform 
the FE]

[TBD: what else do we need in the CE LFB ?]

-- 
Robert Haas
IBM Zurich Research Laboratory
Säumerstrasse 4
CH-8803 Rüschlikon/Switzerland
phone [phone]  fax [phone]  http://www.zurich.ibm.com/~rha


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