Nortel Networks 3500, NTRN10AN manual Generic Framing Procedure and Virtual Concatenation support

Operation, administration, and maintenance (OAM) features 2-99

Table 2-20 (continued)

Fibre Channel extended reach sample distances

STS1-nv	Round Trip Delay	Distance	STS3c-nv	Round Trip Delay	Distance
	(∝s)	(kms)		(∝s)	(kms)
	See Note 1	See Note 2			See Note 2
3	60950	6095
2	91430	9143
1	182860	18286
See Note 3

Note 1: When measuring round trip delay, please be aware that round trip latency measurement (RTDELAY) returns the network latency to an accuracy of +/- 1 ms.

Note 2: Approximation assuming no network element propagation delays and a 5 microsecond / kilometer fiber propagation delay.

Note 3: For Contiguous Concatenation the extended reach supported distances are: STS1 = 18266 kms

STS3c = 5908 kms STS12c = 1477 kms STS24c = 987 kms

Generic Framing Procedure and Virtual Concatenation support

The OPTera Metro 3500-based implementation for point-to-point Ethernet and storage connectivity services uses the GFP and VCAT standards.

Generic Framing Procedure (GFP)

GFP (Generic Framing Procedure) is an ITU standard (G.7041) which describes a flexible mapping technique for transparent transport of multiple protocols in SONET.

The GFP provides an efficient mechanism for Gigabit Ethernet (GE) and Fibre Channel (FICON and FC-100) transport over a SONET core network via efficiently mapping varying client signals into SONET STS frames.

GFP defines two different implementations: Transparent GFP (GFP-T), for byte-oriented data streams that require low latency transmission, and Framed-mapped GFP (GFP-F), which maps one frame or packet of client signal in one GFP frame. The GFP-T mapping scheme is transparent, as control characters are not interpreted but generally encoded and transmitted. The far-end GFP client must however have knowledge of the client signal type in order to correctly handle client-specific issues. GFP-T is recommended for SAN service. GFP-F processes client signal data streams on a Protocol Data Unit (PDU) basis and maps these streams into GFP-F frames one packet at a time. GFP-F is recommended for Ethernet services as it provides flow control capability as well as performance monitoring (Operational Measurements (OM) and Performance Monitoring (PM)).

Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004