SONET-based distance extensions for ESCON/FICON/Fibre-channel services

Overview

This section details the functionality of SONET-based SAN distance extension supported by the LNW73. For other information on the functionality of the LNW73, see Ethernet/SAN circuit packsand Differential delay buffers.

ESCON design guidelines

ESCON services enter Alcatel-Lucent 1665 DMX or Alcatel-Lucent 1665 DMXtend through ESCON PTM attached to LNW73 plug-in circuit and are routed out OC48/192 SONET interfaces from SONET plug-ins in slot main-1 (and main-2, if protection is desired). The SONET signal can be routed through any number of intermediate SONET systems (including none) and terminates into another Alcatel-Lucent 1665 DMX or Alcatel-Lucent 1665 DMXtend to provide a network transport of ESCON services.

When a shelf is equipped with non-VLF Mains, an LNW73 may be placed in slots fn-a-1,fn-b-1,fn-c-1, fn-d-1 or growth-1 (5 slots). When the shelf is equipped with VLF Mains, LNW73 can occupy both slots 1 and 2 of a Function/Growth unit. Up to 4 ESCON services may be provided in a single LNW73 plug-in, each service requiring 4 STS-1 bandwidth reserved in the SONET domain. A Alcatel-Lucent 1665 DMX/OC48 system can provide 12 ESCON services (limited by SONET bandwidth).

A Alcatel-Lucent 1665 DMX/OC192 system with non-VLF Mains can provide 20 ESCON services (limited by the number of slots that may be equipped with LNW73). When equipped with VLF Mains, it can provide up to 40 ESCON services.

Reliability/Line and pack protection options

To protect against SONET network failures and main pack failures, Alcatel-Lucent 1665 DMX can be equipped with redundant circuit packs in both main slots and can be provisioned for UPSR or BLSR protection. To protect against SONET network failures and main pack failures, Alcatel-Lucent 1665 DMX can be equipped with redundant circuit packs in both main slots and be provisioned for UPSR protection. Using SONET protection significantly increases the reliability of individual end-to-end ESCON services.

Circuit pack equipage and provisioning

Each LNW73/73C used must be set to select the pack type of ESCON (see ED-EQPT). Each port to be used must be equipped with an Alcatel-Lucent specified ESCON Pluggable Transmission Module (PTM). A PTM is similar in functionality to a GBIC pluggable unit. If a Virtual Concatenated (VCAT) signal format is desired, the ED-DPORT-DATA command is used to select it.

Circuit bandwidth choices

A full rate ESCON service may be provisioned as a SONET STS-1-4v (VCAT), STS-3c-2v(VCAT) or a STS-12c Contiguously Concatenated (CCAT). The most bandwidth efficient is STS-1-4v.

Interface specifications to ESCON interfaces

Alcatel-Lucent 1665 DMX/Alcatel-Lucent 1665 DMXtend use standards compatible PTM modules. See Chapter 10, Technical specifications for optical specification, loss budget, connector and fiber type requirements.

Distance limitations/transmission delay engineering

Distance between the ESCON equipment and the Alcatel-Lucent 1665 DMX/Alcatel-Lucent 1665 DMXtend are typically limited by the interface link specification of the ESCON interface.

The total distance allowed including the SONET extension is typical a function of the delay requirements of the ESCON application.

Synchronous ESCON applications typically suffer performance droop if the application is subjected to more than 100 microseconds of one way transmission delay (the equivalent of delay through 20 km of fiber). For planning purposes, each Alcatel-Lucent 1665 DMX adds the equivalent 25 microseconds or 5 km of fiber. Therefore, synchronous ESCON applications would suffer droop if the total actual fiber distance (adding the ESCON to Alcatel-Lucent 1665 DMX and Alcatel-Lucent 1665 DMX to Alcatel-Lucent 1665 DMX links) is more than 10 km.

Asynchronous ESCON applications are much more tolerant to transmission delay, typically able to function at delays of 1000 microseconds (200 km) or longer. Each Alcatel-Lucent 1665 DMX/Alcatel-Lucent 1665 DMXtend or other SONET system in the path of such a network would add the equivalent of 5 km of fiber.

Full-rate FICON/FC design guidelines

FICON/FC services enter Alcatel-Lucent 1665 DMX or Alcatel-Lucent 1665 DMXtend through FICON/FC PTM attached to LNW73 plug-in circuit is routed out OC48/192 SONET interfaces from SONET plug-in in slot main-1 (and main-2, if protection is desired).

The SONET signal can be routed through any number of intermediate SONET systems (including zero) and terminates into another Alcatel-Lucent 1665 DMX or Alcatel-Lucent 1665 DMXtend to provide a network transport of a FC/FICON service.

An LNW73 may be placed in slots fn-a-1,fn-b-1,fn-c-1, fn-d-1 or growth-1 (5 slots) of a Alcatel-Lucent 1665 DMX. When the shelf is equipped with VLF Mains, LNW73 can occupy both slots 1 and 2 of a Function/Growth unit.

Up to 2 full rate 1G FICON/FC services (or one 2G FICON/FC service) may be provided in a single LNW73 circuit pack, each service requiring 19 STS-1 or 6 STS-3c bandwidth units reserved in the SONET domain (37 STS-1 or 12 STS-3c for 2G FICON/FC).

When operating in asynchronous Fibre Channel (FC) mode, 2 ports are available at 2Gbps FC, or 4 ports at 1Gbps FC, or 1 port at 2Gbps FC and 2 ports of 1Gbps FC. When operating in synchronous FC mode, 1 port is available at 2Gbps FC, or 2 at 1Gbps FC.

A Alcatel-Lucent 1665 DMX/OC48 system can provide 2 full rate FICON/FC 1G services (limited by SONET bandwidth).

A Alcatel-Lucent 1665 DMX/OC192 system can provide 10 FICON/FC 1G services (limited by the number of slots that may be equipped with LNW73).

Buffer-to-buffer credits are handled exclusively by FICON/FC switches/devices.

Reliability/Line and pack protection options

To protect against SONET network failures and main pack failures, Alcatel-Lucent 1665 DMX can be equipped redundant circuit packs in both main slots and be provisioned for UPSR or BLSR protection.

Using SONET Protection dramatically increases the reliability of end to end FICON/FC services.

Circuit pack equipage and provisioning

Each LNW73 used must be set to select the pack type of FICON/FC (see ED-EQPT). Each port to be used must be equipped with an Alcatel-Lucent specified FC/FICON Pluggable PTM. A PTM is similar in functionality to a GBIC pluggable unit. If a VCAT signal format is desired, the ED-DPORT-DATA command is used to select it.

Circuit bandwidth choices

A full rate 1G FICON/FC service may be provisioned as a SONET STS-1-19v (VCAT), STS-3c-6v(VCAT). The most bandwidth efficient is STS-3c-6v. A full rate 2G FICON/FC service may be provisioned as a SONET STS-1-37v (VCAT), STS-3c-12v (VCAT). The most bandwidth efficient is STS-3c-12v.

Interface specifications to FICON/FC interfaces

Alcatel-Lucent 1665 DMX uses standards compatible PTMs. The same PTM works for both FICON and FC and both 1G and 2G. See Chapter 10, Technical specifications for optical specification, loss budget, connector and fiber type requirements.

Distance limitations/transmission delay engineering

Distance between the FICON/FC equipment and the Alcatel-Lucent 1665 DMX are typically limited by the interface link specification of the FICON/FC interface.

The total distance allowed including the SONET extension is typically a function of the delay requirements of the FICON/FC application.

Synchronous FICON/FC applications performance typically suffers if the application is subjected to more than 600 microseconds of one way transmission delay (the equivalent of delay through 120 km of fiber). Refer to your particular client equipment engineering rules for distance limitations. For planning purposes, each Alcatel-Lucent 1665 DMX adds the equivalent 25 microseconds or 5 km of fiber.

Asynchronous FICON/FC applications are much more tolerant to transmission delay, typically able to function at delays of 1000 microseconds (200 km) or longer. Many FC switches offer extended buffer credits for asynchronous applications that allow up to 3600 microseconds of delay without performance droop. Each Alcatel-Lucent 1665 DMX or other SONET system in the path of such a network would add the equivalent of 5 km of fiber.

FC/FICON services-extended distances - BB credits managed in Alcatel-Lucent 1665 DMX/Alcatel-Lucent 1665 DMXtend

To extend asynchronous FICON/FC applications beyond the buffer to buffer credit limits of the attached FC Switches, Alcatel-Lucent 1665 DMX and Alcatel-Lucent 1665 DMXtend can be provisioned to manage the BB Credits and eliminate performance droop related to insufficient BB credit across the network. This implementation is based on the ITU G.7041 and T11 FC-BB-3_GFPT standards work and provides sufficient credits for full performance at 2500 km for 2G services.

To use this mode, the gfptype (in the ED-DPORT-DATA command) must be provisioned to ASYNC-FC (even if it is a FICON service). Buffer credits are automatically adjusted within Alcatel-Lucent 1665 DMX and no additional provisioning required. Attached FICON/FC devices should be provisioned to use for R_RDY flow control (as opposed to proprietary Inter-Switch Link (ISL) flow control schemes.

Illustrative examples of some FC switch configurations are provided below.

EMC certification

Alcatel-Lucent 1665 DMX has been qualified by EMC eLab Testing and with Brocade Fabric Aware Testing. Alcatel-Lucent 1665 DMX has been tested with various FC/FICON switches used with storage equipment. This testing has yielded some simple guidelines (listed below) that need to be followed to ensure smooth interworking between Alcatel-Lucent 1665 DMX and some of the FC/FICON switches listed above.

General FC/FICON equipment port configuration for connection to Alcatel-Lucent 1665 DMX

Please use the following guidelines to ensure interoperability between FC/FICON equipment and Alcatel-Lucent 1665 DMX.

To assure minimal link start up and recovery times, the following configurations are recommended for all ports attached to Alcatel-Lucent 1665 DMX:

To use buffer credits in Alcatel-Lucent 1665 DMX when gfptype is set to async-FC, configure ports to use R_RDY mode buffer credit management instead of proprietary link buffer credit management.

If compression is desired on Alcatel-Lucent 1665 DMX and gfptype is set to async-FC, set the number of link buffer credits to 8 or less, otherwise the operational state of compression will stay disabled.

Brocade interworking examples

Please use the following guidelines to ensure interoperability between the specified Brocade equipment and Alcatel-Lucent 1665 DMX.

Brocade Silkworm 3800

Perform the following tasks on all ports connected to the Alcatel-Lucent 1665 DMX:

In addition, to use buffer credits on Alcatel-Lucent 1665 DMX when gfptype is set to async-FC, use portcfgISLMODE {portnum}, {1, not 0}.

To use compression on Alcatel-Lucent 1665 DMX when gfptype is set to async-FC, use switchdisable, then use the configure command to set fabric.ops.BBCredit to 8 or less.

Brocade Silkworm 2250

Perform the following tasks on all ports connected to the Alcatel-Lucent 1665 DMX:

In addition, to use buffer credits on Alcatel-Lucent 1665 DMX when gfptype is set to async-FC, use switchdisable, then use the configure command to set fabric.ops.longdistance=1

To use compression on Alcatel-Lucent 1665 DMX when gfptype is set to async-FC, use switchdisable, then use the configure command to set fabric.ops.BBCredit to 8 or less.

Cisco MDS 9120 or MDS 9216 interworking examples

Please use the following guidelines to ensure interoperability between the Cisco MDS 9120 or MDS 9216 equipment and Alcatel-Lucent 1665 DMX.

Perform the following tasks on all ports connected to the Alcatel-Lucent 1665 DMX:

In addition, to use buffer credits on Alcatel-Lucent 1665 DMX when gfptype is set to async-FC, it is important to note that Cisco uses ISL mode as R_RDY mode by default.

To use compression on Alcatel-Lucent 1665 DMX when gfptype is set to async-FC, through the GUI, click on FC port, then click on BBCredit and then set admin BBCredit to 8 or less.

MC Data Sphereon 4500 interworking examples

Please use the following guidelines to ensure interoperability between the MC Data Sphereon 4500 equipment and Alcatel-Lucent 1665 DMX.

Perform the following tasks on all ports connected to the Alcatel-Lucent 1665 DMX:

In addition, to use buffer credits on Alcatel-Lucent 1665 DMX when gfptype is set to async-FC, it is important to note that Sphereon uses ISL mode as R_RDY mode by default.

To use compression on Alcatel-Lucent 1665 DMX when gfptype is set to async-FC, set any port numbered "4" or higher to use 5 credits (ports 0–3 use 12 credits).

November 2011Copyright © 2011 Alcatel-Lucent. All rights reserved.