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Artifact artf6568 : Properties of Ports and Links

Tracker:	Schema Progress
Title:	Properties of Ports and Links
Description:	Ports and Links can often be augmented with these properties: * name -- a human readable name for the port or link * encoding -- the 'layer' of the port or link * label -- the channel identifier of the port or link * capacity -- the maximum data flow that can be transport through the port or over the link * MTU -- the maximum transfer unit (thus packet size excluding headers) of a frame or packet * (for links only) latency -- the one-way delay Proposal: NML base will define name, encoding and label, but no other properties.
Submitted By:	Freek Dijkstra
Submitted On:	07/11/2012 8:43 PM EDT
Last Modified:	11/30/2012 7:57 AM EST
Closed:	11/30/2012 7:57 AM EST

	Status / Comments		Change Log		Associations		Attachments

Status
Status:*	Completed
Category:*	UML schema
Priority: *	4
Assigned To: *	None

Comments

Jeroen van der Ham: 11/30/2012 7:57 AM EST
	Action:	Update Closed set to 11/30/2012 Status changed from Last Call to Completed

Jason Zurawski: 08/16/2012 7:45 AM EDT
	Comment:	thanks for the clarification - agree fully
	Action:	Update

Freek Dijkstra: 08/16/2012 7:44 AM EDT

Comment:

Jason: It's still allowed. The proposals is to "not define capacity and MTU in the base schema.". So it has to be defined in a technology extension. E
.g.:

 <nml:Port id="....">
    <nmleth:capacity>1000000000</nmleth:capacity>
 </nml:Port>

The disadvantage is that e.g. an Ethernet extension may define capacity differently from e.g. an IP extension.

The rationale was posted in the OGF 35 notes:

There is no clear definition of MTU and capacity. MTU and PDU often gets mixed up. Capacity can mean the link capacity, or the maximum achievable 
bandwidth. Eg. 1 Gbit/s Ethernet carries 1.25 Gbaud with 4/5 encoding, but due to interframe gap, preamble, header, CRC and footer the effective 
bandwidth is only 0.941482 Mbit/s. http://sd.wareonearth.com/~phil/net/overhead/. This depends on MTU.

The bottom line is that we couldn't come up with a definition that would apply to all technologies.

Action:

Update

Jason Zurawski: 08/16/2012 7:31 AM EDT
	Comment:	How will items like latency, MTU, and capacity be decorated onto ports/links if we disallow this?
	Action:	Update

Freek Dijkstra: 07/11/2012 8:44 PM EDT

Comment:

Comment from OGF 35:


Encoding property is useful, akin to GMPLS to specify the type of Port (e.g. Ethernet VLAN Port, MAC Port, Wavelength Port, etc.)

There is no clear definition of MTU and capacity. MTU and PDU often gets mixed up. Capacity can mean the link capacity, or the maximum achievable 
bandwidth. Eg. 1 Gbit/s Ethernet carries 1.25 Gbaud with 4/5 encoding, but due to interframe gap, preamble, header, CRC and footer the effective 
bandwidth is only 0.941482 Mbit/s. http://sd.wareonearth.com/~phil/net/overhead/. This depends on MTU.

Action:

Update

Freek Dijkstra: 07/11/2012 8:43 PM EDT
	Action:	Create

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