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What is port fillword

What is port fillword

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Introduction

What does “fillword” in SAN switch documents mean?


Detailed Information

The word “fillword” is commonly used for Brocade switches such as 300, 5100, 5300, DCX-S, and DCX-4S. Fillword is OrderdSet that is sent between data frames. In a simple term, it is the minimum-size frame that fills space between data frames or fills space when there is no data to send. IDLE was used as fillword when the max link speed was 4Gb. When 8Gb switch was introduced, ARBff was adopted instead of IDLE mostly because it could contribute to lower bit error. IDLE that used for initialization was also changed to ARBff, along with the fillword change.


Brocade switches that support 8Gbcan configure the fillword setting by portCfgFillword command. Below is an output of “portcfgfillword --help” .

admin> portcfgfillword --help

Usage: portCfgFillWord [SlotNumber/]PortNumber Mode  [Passive]

Mode: 0/-idle-idle      - IDLE in Link Init, IDLE as fill word (default)

          1/-arbff-arbff   - ARBFF in Link Init, ARBFF as fill word

          2/-idle-arbff    - IDLE  inLink Init, ARBFF as fill word (SW)

          3/-aa-then-ia  - If ARBFF/ARBFF failed, then do IDLE/ARBFF

Passive: 0/1

admin>

0: Use IDLE for initialization as 4Gb switches do.

1: Always use ARBff.

2: Use IDLE for initialization and use ARBff for between data frames.

3: Use ARBff for initialization first. If it fails, use IDLE. Use ARBff for between data frames.

When we use 8Gb switches, “1” basically works. However, since sometimes some switches do not work with ARBff, if you are not confident, it is safe to use “3”. Despite the circumstances, strangely the default setting has value “0” (use IDLE for initialization).

You can check the current status by “portCfgShow”. (Below output shows the setting is “3”)


Ports of Slot 7         0   1   2   3     4   5   6   7     8   9  10  11    12  13  14  15

----------------------+---+---+---+---+-----+---+---+---+-----+---+---+---+-----+---+---+---

Speed                  AN  AN  AN  AN    AN  AN  AN  AN    AN  AN  AN  AN    AN  AN  AN  AN

Fill Word(On Active)    3   3   3   3     3   3   3   3     3   3   3   3     3   3   3   3

Fill Word(Current)      3   3   3   3     3   3   3   3     3   3   3   3     3   3   3   3

AL_PA Offset 13        ..  ..  ..  ..    ..  ..  ..  ..    ..  ..  ..  ..    ..  ..  ..  ..

Trunk Port             ON  ON  ON  ON    ON  ON  ON  ON    ON  ON  ON  ON    ON  ON  ON  ON

Long Distance          ..  ..  ..  ..    ..  ..  ..  ..    ..  ..  ..  ..    ..  ..  ..  ..

Please keep in mind that if your switch is 16Gb model such as 6510, 6520, and DCX-8510, there is no such settings and they use ARBff for both initialization and between-frames.


As for MDS switches, they use ARBffas default if the switches support 8Gb/16Gb. So, we usually do not have to change the settings but, if needed, we can change it through switchport fill-pattern command.

The original content is https://community.emc.com/thread/201938 (written in Japanese)

                                                                                                                                              



Author: Yutaro






Labels (1)
8 Replies
RRR
5 Osmium

Re: What is port fillword

How can I check what the current value of this fillword setting is?

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jungs2
2 Bronze

Re: Re: What is port fillword

Consider using the portCfgShow command to verify the Fill Word setting.

For example: To display the port configuration settings on a Brocade 5100 for a range of ports specified by their index numbers:


switch:admin> portcfgshow -i 3-5

Speed 8G 8G 8G

Fill Word(On Active) 0 0 0

Fill Word(Current) 0 0 0

...

(Output truncated)

Fill Word (On Active)

Displays the fill word setting that will take effect after the next time the port goes offline and comes back Possible values are 0(Idle-Idle), 1(arbff-arbff), 2(Idle-arbff), or 3(A-A then SW I-A).

Fill Word (Current)

Displays the currently effective fill word setting. Possible values are 0(Idle-Idle), 1(arbff-arbff), 2(Idle-arbff), or 3(A-A then SW I-A).

(Source: Brocade Fabric OS v7.4.1 Command Reference)

Please note:  For most environments, Brocade recommends using Mode 3, as it provides more flexibility and compatibility with a wide range of devices. (Source: Brocade Fabric OS v7.4.1 Admin Guide)

It might be possible, that a end device vendor requires a different Fill Word; for example when connecting a Cisco UCS to a Brocade 8Gbps switch will require Fill Word = 2.

I hope this will help.

Best regards,

Swen

0 Kudos
RRR
5 Osmium

Re: Re: What is port fillword

When I do a portcfgshow command:

portcfgshow -i 0-1

Index:                 0   1

--------------------+---+---

Octet Speed Combo     1   1

Speed                8G  8G

AL_PA Offset 13      ..  ..

Trunk Port           ON  ON

Long Distance        LD  LD

VC Link Init         ON  ON

Locked L_Port        ..  ..

Locked G_Port        ON  ON

Disabled E_Port      ..  ..

Locked E_Port        ..  ..

ISL R_RDY Mode       ..  ..

RSCN Suppressed      ..  ..

Persistent Disable   ..  ..

LOS TOV mode          0   0

NPIV capability      ON  ON

NPIV PP Limit        126 126

NPIV FLOGI Logout    ..  ..

QOS Port             ..  ..

EX Port              ..  ..

Mirror Port          ..  ..

Rate Limit           ..  ..

Credit Recovery      ON  ON

Fport Buffers        ..  ..

Eport Credits        ..  ..

Port Auto Disable    ..  ..

CSCTL mode           ..  ..

D-Port mode          ..  ..

D-Port over DWDM     ..  ..

Compression          ..  ..

Encryption           ..  ..

FEC                  ..  ..

FEC via TTS          ..  ..

Fault Delay          0   0

Non-DFE              ..  ..

SIM Port             ..  ..

TDZ mode                 ..  ..

  where AE:QoSAutoEnable, AN:AutoNegotiate, ..:OFF, -:NotApplicable, ??:INVALID,

LM:L0.5

It could be me, but I'm not seeing anything about fillwords.

0 Kudos
jungs2
2 Bronze

Re: Re: What is port fillword

Which switch and firmware are in use?

0 Kudos
jungs2
2 Bronze

Re: Re: What is port fillword

Instead of searching for CLI commands and outputs, consider doing a FREE Dell EMC SAN Health Check to get the following:

  • Inventory of all attached storage devices,
  • Visio diagram showing connectivity, and
  • Excel file summarizing, and detailing, all switches and directors.

Additionally, you can collect performance data; highlight best practice violations, and more.

If you like, you can download the Dell EMC SAN Health tool here:

http://www.emc.com/partnerships/technology-alliances/brocade-promo/install-emc-san-health.zip


Best regards,


Swen

0 Kudos
RRR
5 Osmium

Re: Re: What is port fillword

I know the Brocade SAN Health tool which does exactly what you described. I've looked for the fillword setting and it's not there. Is the Dell EMC SAN Health in any way different and does it provide that fillword setting?

The switches are Brocade 6520 and 6505 running on FOS 7.4.1a

0 Kudos
jungs2
2 Bronze

Re: Re: What is port fillword

If you are running Connectrix DS-65xxB switches, the answer is simple that these switches does not have a port fill word setting.

The fill word is not applicable for Gen-5 (16-Gbps) platform switches. (Source Brocade FOS 7.4 Admin Guide)

Having an older switch, the CLI commands will work and the SAN Health Report will show the Fill Word setting, too.


For example a capture of a Switch Summary and Port Details for a DS-5000B will show the Fill Word:

portConfigdetails.JPG.jpg

Best regards,

Swen

RRR
5 Osmium

Re: Re: What is port fillword

thanks! That explains why I couldn't find it.

0 Kudos