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Fibre Channel (SAN)

Posts: 0


Is "ISL_R_READY" mode required for Extended Fabrics?

Doesn't look like it... Normally with local/campus ISL's we don't use it...

The LongDistance will be set to LD.

Is ISL_R_Ready required to be on??

External Moderator
Posts: 5,620
Registered: ‎02-23-2004


usually is not necessary.

Posts: 0


A few things: this scenario applies to 2 sites in different cities sparated by 82Km. Multimode fiber is fine since we're connecting the Brocade to a Nortel device at each end.

  • Extended Fabrics license is required

  • make sure PID format is consistent (the same) across ALL switches in the fabric

  • make sure every switch has a different Domain ID

  • Even if you're using CWDM/DWDM device such as Nortel, the cards that connect to your equipment may be TDM cards (to split the laser signal). In this case the following is required:

  • hard-code all E-ports to the same speed (portcfgspeed 1/0, 1)

  • configure the port for R_RDY mode (portcfgislmode 1/0, 1)

  • disable trunking on the port (portcfgtrunkport 1/0, 0)

  • LD is dynamic setting of the buffers based on the distance but it better to use LS (static) if you know the distance. If the diatnce between the 2 sites is 82Km for instance chose 90 (portcfglongdistance 1/0 ls 0 90)

  • the config must be the same for the remote port

  • your portcfgshow 1/0 on port should look like this: (this example is from a 48K with Fbaric OS 6 or above)

Area Number: 0

Speed Level: 1G (portcfgspeed 1/0, 1) hard coding the WAN ports to 1Gbps

AL_PA Offset 13: OFF

Trunk Port OFF (portcfgtrunkport 1/0, 0) this configuration is not applicable to a port configured for ISL R_RDY mode

Long Distance LS (portcfglongdistance 1/0 LS 0 90) using LS for static distance configuration

VC Link Init OFF (portcfglongdistance 1/0 LS 0 90) for an ISL configured for R_RDY mode, this setting should be set to 0

Desired Distance 90 Km (portcfglongdistance 1/0 LS 0 90) the longest distance between NJ& NY is 82Km as provided by carrier. We're specifying 90Km

Reserved Buffers 51 (based on the distance specified, 51 buffers were statically allocated to this E-port)

Locked L_Port OFF

Locked G_Port OFF

Disabled E_Port OFF

ISL R_RDY Mode ON (portcfgislmode 1/0, 1) this flow control setting is optimal for TDM cards installed on the Nortel devices

RSCN Suppressed OFF

Persistent Disable OFF

NPIV capability ON


Mirror Port OFF

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