Nortel Networks OPTera Metro 3500 - Manual (Page 137)

Operation, administration, and maintenance (OAM) features 2-99
Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
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)).
3 60950 6095
2 91430 9143
1
See Note 3
182860 18286
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
Table 2-20 (continued)
Fibre Channel extended reach sample distances
STS1-nv Round Trip Delay
( µs)
See Note 1
Distance
(kms)
See Note 2
STS3c-nv Round Trip Delay
( µs)
Distance
(kms)
See Note 2