Range using single-mode SFPs across multi-mode fiber - was Re: NANOG Digest, Vol 47, Issue 56
On Wed, Dec 14, 2011 at 2:34 PM, oliver rothschild <orothschild@gmail.com> wrote:
This is my first e-mail to the list and I hope it is not entirely
As a suggestion, could you please in the future not use a subject such as "Re: NANOG Digest, Vol 47, Issue 56" for posts. It is MUCH better to use a topical subject line (see my suggestion above); that helps people who filter their mail keep track of threads and topics. Regards Marshall
inappropriate. We are attempting to use Juniper single-mode SFPs (LX variety) across multi-mode fiber. Standard listed distance is always for SFPs using the appropriate type of fiber. Does anyone out there know how much distance we are likely to get? Thanks for your help in advance.
On Wed, Dec 14, 2011 at 2:07 PM, <nanog-request@nanog.org> wrote:
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Today's Topics:
1. Re: EFF call for signatures from Internet engineers against censorship (Suresh Ramasubramanian) 2. RE: EFF call for signatures from Internet engineers against censorship (O'Reirdan, Michael) 3. Recognized Address Transfer Facilitators (was: Your Christmas Bonus Has Arrived) (John Curran) 4. Re: Recognized Address Transfer Facilitators (was: Your Christmas Bonus Has Arrived) (Leigh Porter) 5. Re: EFF call for signatures from Internet engineers against censorship (Suresh Ramasubramanian) 6. Re: Your Christmas Bonus Has Arrived (bmanning@vacation.karoshi.com) 7. Re: Recognized Address Transfer Facilitators (was: Your Christmas Bonus Has Arrived) (Justin M. Streiner) 8. Re: Recognized Address Transfer Facilitators (was: Your Christmas Bonus Has Arrived) (Mark Tinka) 9. Multiple ISP Load Balancing (Holmes,David A)
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Message: 1 Date: Wed, 14 Dec 2011 15:42:51 +0530 From: Suresh Ramasubramanian <ops.lists@gmail.com> To: Hal Murray <hmurray@megapathdsl.net> Cc: nanog@nanog.org Subject: Re: EFF call for signatures from Internet engineers against censorship Message-ID: <CAArzuouqU2SivNgcE-3ipe-AwSq7v7N1H4wWqOxzxsP8hxYCOA@mail.gmail.com> Content-Type: text/plain; charset=UTF-8
I would strongly suggest that operators work with their legal departments to endorse this paper by Crocker and others.
If other ISP organizations (such as say MAAWG) come out with something, other operators could sign on to that as well.
The EFF petition has way too much propaganda and far less content than would be entirely productive in a policy discussion.
--srs
On Wed, Dec 14, 2011 at 12:51 PM, Hal Murray <hmurray@megapathdsl.net> wrote:
?Security and Other Technical Concerns Raised by the ? ?DNS Filtering Requirements in the PROTECT IP Bill ?Authors: ? ?Steve Crocker, Shinkuro, Inc. ? ?David Dagon, Georgia Tech ? ?Dan Kaminsky, DKH ? ?Danny McPherson, Verisign, Inc. ? ?Paul Vixie, Internet Systems Consortium
-- Suresh Ramasubramanian (ops.lists@gmail.com)
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Message: 2 Date: Wed, 14 Dec 2011 11:36:59 +0000 From: "O'Reirdan, Michael" <Michael_OReirdan@Cable.Comcast.com> To: Suresh Ramasubramanian <ops.lists@gmail.com>, Hal Murray <hmurray@megapathdsl.net> Cc: "nanog@nanog.org" <nanog@nanog.org> Subject: RE: EFF call for signatures from Internet engineers against censorship Message-ID: <B13238AB0CB1514B9509DEEE5F98F2E00DE39363@PACDCEXMB13.cable.comcast.com>
Content-Type: text/plain; charset="us-ascii"
MAAWG has written voicing its concerns on SOPA and PIPA.
http://www.maawg.org/sites/maawg/files/news/MAAWG_US_Congress_S968-HR3261_Co...
Mike ________________________________________ From: Suresh Ramasubramanian [ops.lists@gmail.com] Sent: 14 December 2011 05:12 To: Hal Murray Cc: nanog@nanog.org Subject: Re: EFF call for signatures from Internet engineers against censorship
I would strongly suggest that operators work with their legal departments to endorse this paper by Crocker and others.
If other ISP organizations (such as say MAAWG) come out with something, other operators could sign on to that as well.
The EFF petition has way too much propaganda and far less content than would be entirely productive in a policy discussion.
--srs
On Wed, Dec 14, 2011 at 12:51 PM, Hal Murray <hmurray@megapathdsl.net> wrote:
Security and Other Technical Concerns Raised by the DNS Filtering Requirements in the PROTECT IP Bill Authors: Steve Crocker, Shinkuro, Inc. David Dagon, Georgia Tech Dan Kaminsky, DKH Danny McPherson, Verisign, Inc. Paul Vixie, Internet Systems Consortium
-- Suresh Ramasubramanian (ops.lists@gmail.com)
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Message: 3 Date: Wed, 14 Dec 2011 12:18:56 +0000 From: John Curran <jcurran@arin.net> To: "Patrick W. Gilmore" <patrick@ianai.net> Cc: NANOG list <nanog@nanog.org> Subject: Recognized Address Transfer Facilitators (was: Your Christmas Bonus Has Arrived) Message-ID: <131B2DA4-7C99-4DB8-924A-EBCB27EF9BF0@arin.net> Content-Type: text/plain; charset="us-ascii"
On Dec 14, 2011, at 12:40 AM, Patrick W. Gilmore wrote:
I believe this company is the one that sold the MS & Borders blocks, so they may be "legit" (whatever that means in this context).
I also do not know what "legit" means in this context, but will note that we have added a public list of all recognized specified transfer facilitators to the ARIN web site:
<https://www.arin.net/resources/transfer_listing/facilitator_list.html>
Facilitators are aware of ARIN's address transfer policies and agree to comply with same. Note that any qualifying parties may transfer space in compliance with policy, but folks may find it easier to work with one of these facilitators to find a matching party for transfer. Facilitators may make use of information in the optional Specified Transfer Listing Service (which lists those who have space available or prequalify as a recipient) but not required to do so. Similarly, parties which may have space available for transfer or wish to prequalify in advance to receive address space via transfer may also register in the Specified Transfer Listing Service (STLS). More information is available on the ARIN web site <www.arin.net> under "IPv4 SPECIFIED TRANSFER OPTIONS" section.
FYI (and Happy Holidays :-) /John
John Curran President and CEO ARIN
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Message: 4 Date: Wed, 14 Dec 2011 12:30:06 +0000 From: Leigh Porter <leigh.porter@ukbroadband.com> To: John Curran <jcurran@arin.net> Cc: NANOG list <nanog@nanog.org> Subject: Re: Recognized Address Transfer Facilitators (was: Your Christmas Bonus Has Arrived) Message-ID: <8C3137B6-7690-4CF5-85B2-594E450CDB7B@ukbroadband.com> Content-Type: text/plain; charset="us-ascii"
I love the anti v6 stuff on some of their sites!
http://www.iptrading.com/news/news.htm
-- Leigh
On 14 Dec 2011, at 12:21, "John Curran" <jcurran@arin.net> wrote:
On Dec 14, 2011, at 12:40 AM, Patrick W. Gilmore wrote:
I believe this company is the one that sold the MS & Borders blocks, so they may be "legit" (whatever that means in this context).
I also do not know what "legit" means in this context, but will note that we have added a public list of all recognized specified transfer facilitators to the ARIN web site:
<https://www.arin.net/resources/transfer_listing/facilitator_list.html>
Facilitators are aware of ARIN's address transfer policies and agree to comply with same. Note that any qualifying parties may transfer space in compliance with policy, but folks may find it easier to work with one of these facilitators to find a matching party for transfer. Facilitators may make use of information in the optional Specified Transfer Listing Service (which lists those who have space available or prequalify as a recipient) but not required to do so. Similarly, parties which may have space available for transfer or wish to prequalify in advance to receive address space via transfer may also register in the Specified Transfer Listing Service (STLS). More information is available on the ARIN web site <www.arin.net> under "IPv4 SPECIFIED TRANSFER OPTIONS" section.
FYI (and Happy Holidays :-) /John
John Curran President and CEO ARIN
______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please visit http://www.symanteccloud.com ______________________________________________________________________
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Message: 5 Date: Wed, 14 Dec 2011 18:01:06 +0530 From: Suresh Ramasubramanian <ops.lists@gmail.com> To: "O'Reirdan, Michael" <Michael_OReirdan@cable.comcast.com> Cc: "nanog@nanog.org" <nanog@nanog.org>, Hal Murray <hmurray@megapathdsl.net> Subject: Re: EFF call for signatures from Internet engineers against censorship Message-ID: <CAArzuotafMx+1mRFT9dLqYyRvhyFBsPg=Cir48-Ez=QZxLLEPw@mail.gmail.com> Content-Type: text/plain; charset=UTF-8
Wonderful. I would urge SPs based stateside to strongly consider endorsing the MAAWG comments.
thanks suresh
On Wed, Dec 14, 2011 at 5:06 PM, O'Reirdan, Michael <Michael_OReirdan@cable.comcast.com> wrote:
MAAWG has written voicing its concerns on SOPA and PIPA.
http://www.maawg.org/sites/maawg/files/news/MAAWG_US_Congress_S968-HR3261_Co...
Mike ________________________________________ From: Suresh Ramasubramanian [ops.lists@gmail.com] Sent: 14 December 2011 05:12 To: Hal Murray Cc: nanog@nanog.org Subject: Re: EFF call for signatures from Internet engineers against censorship
I would strongly suggest that operators work with their legal departments to endorse this paper by Crocker and others.
If other ISP organizations (such as say MAAWG) come out with something, other operators could sign on to that as well.
The EFF petition has way too much propaganda and far less content than would be entirely productive in a policy discussion.
--srs
On Wed, Dec 14, 2011 at 12:51 PM, Hal Murray <hmurray@megapathdsl.net> wrote:
?Security and Other Technical Concerns Raised by the ? ?DNS Filtering Requirements in the PROTECT IP Bill ?Authors: ? ?Steve Crocker, Shinkuro, Inc. ? ?David Dagon, Georgia Tech ? ?Dan Kaminsky, DKH ? ?Danny McPherson, Verisign, Inc. ? ?Paul Vixie, Internet Systems Consortium
-- Suresh Ramasubramanian (ops.lists@gmail.com)
-- Suresh Ramasubramanian (ops.lists@gmail.com)
------------------------------
Message: 6 Date: Wed, 14 Dec 2011 14:10:52 +0000 From: bmanning@vacation.karoshi.com To: Chaim Rieger <chaim.rieger@gmail.com> Cc: nanog@nanog.org Subject: Re: Your Christmas Bonus Has Arrived Message-ID: <20111214141052.GA7933@vacation.karoshi.com.> Content-Type: text/plain; charset=us-ascii
On Tue, Dec 13, 2011 at 10:07:44PM -0800, Chaim Rieger wrote:
What do you have for those that don't do the whole Jesus thing ?
babalyonian fertility icons? (you -did- bring an evergreen tree into your home, yes?)
/bill
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Message: 7 Date: Wed, 14 Dec 2011 09:16:27 -0500 (EST) From: "Justin M. Streiner" <streiner@cluebyfour.org> To: NANOG list <nanog@nanog.org> Subject: Re: Recognized Address Transfer Facilitators (was: Your Christmas Bonus Has Arrived) Message-ID: <Pine.LNX.4.64.1112140906460.30735@whammy.cluebyfour.org> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
On Wed, 14 Dec 2011, Leigh Porter wrote:
I love the anti v6 stuff on some of their sites!
Some of which seems to float between fear-mongering, possibly mis-appropriated quotes, half-truths and information that is flat-out wrong. I would not trust the judgment and opinions of someone who even admitted in one of their blog posts that they had "no hands-on Service Provider IPv6 experience."
While I can understand why IPv4 address brokers would take a decidedly anti-IPv6 stance (deploying IPv6 cuts into their potential business), that doesn't make it any less underhanded.
jms
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Message: 8 Date: Wed, 14 Dec 2011 22:18:41 +0800 From: Mark Tinka <mtinka@globaltransit.net> To: nanog@nanog.org Cc: John Curran <jcurran@arin.net> Subject: Re: Recognized Address Transfer Facilitators (was: Your Christmas Bonus Has Arrived) Message-ID: <201112142218.42329.mtinka@globaltransit.net> Content-Type: text/plain; charset="us-ascii"
On Wednesday, December 14, 2011 08:30:06 PM Leigh Porter wrote:
I love the anti v6 stuff on some of their sites!
I'd have been more impressed if they actually came up with the stories by themselves, as opposed to linking to existing stories that their link titles take out of context.
Mark.
inappropriate. We are attempting to use Juniper single-mode SFPs (LX variety) across multi-mode fiber. Standard listed distance is always for SFPs using the appropriate type of fiber. Does anyone out there know how much distance we are likely to get? Thanks for your help in advance.
Single mode just has a smaller core size for the smaller "beam" emitted by laser vs. LED. it works although I've never done it outside of a lab (MM is cheaper). As for the distance it theory that should come down to the optics and your transmit power. Hopefully this is just a cable connecting the router to a long line. I've never heard of a 10K MM fiber run since SX optics can't shoot that far. You should be able to get through the 500m or so that MM optics are rated for, but YMMV (errors, light levels, bounces, etc etc)
On 12/14/2011 3:37 PM, Keegan Holley wrote:
Single mode just has a smaller core size for the smaller "beam" emitted by laser vs. LED. it works although I've never done it outside of a lab (MM is cheaper). As for the distance it theory that should come down to the optics and your transmit power. Hopefully this is just a cable connecting the router to a long line. I've never heard of a 10K MM fiber run since SX optics can't shoot that far. You should be able to get through the 500m or so that MM optics are rated for, but YMMV (errors, light levels, bounces, etc etc)
Cisco gives specs for SFP LX over MM (they aren't that great at gig, and really suck at 10G; if you have 50u OM3/OM4 you can do much better at 10G). See SFP/fiber/distance table at http://www.cisco.com/en/US/prod/collateral/modules/ps5455/ps6577/product_dat... We have run LX-over-MM (62.5) on short building runs as a band-aid until SM is available, and trying to do all new building MM with 50u OM3/OM4. We do have some dependence on 62.5u MM - used by our aging Simplex alarm system - which does point-to-point looped token ring <*cough*> on the alarm side. I'm trying to get them to confirm 50u will work point-to-point, but at some non-alarm-points there would be a necessary 50-to-62.5 exchange taking place and I'm not certain how to accomplish that (50->62.5 would likely have tolerable loss, but not 62.5->50). (I would suspect similar results cross-vendor but YMMV) Jeff
2011/12/14 Jeff Kell <jeff-kell@utc.edu>
On 12/14/2011 3:37 PM, Keegan Holley wrote:
Single mode just has a smaller core size for the smaller "beam" emitted by laser vs. LED. it works although I've never done it outside of a lab (MM is cheaper). As for the distance it theory that should come down to the optics and your transmit power. Hopefully this is just a cable connecting the router to a long line. I've never heard of a 10K MM fiber run since SX optics can't shoot that far. You should be able to get through the 500m or so that MM optics are rated for, but YMMV (errors, light levels, bounces, etc etc)
Cisco gives specs for SFP LX over MM (they aren't that great at gig, and really suck at 10G; if you have 50u OM3/OM4 you can do much better at 10G).
See SFP/fiber/distance table at
http://www.cisco.com/en/US/prod/collateral/modules/ps5455/ps6577/product_dat...
They specify that line conditioning cables were used. I would say if you're going to bother purchasing why not purchase SM?
We have run LX-over-MM (62.5) on short building runs as a band-aid until SM is available, and trying to do all new building MM with 50u OM3/OM4. We do have some dependence on 62.5u MM - used by our aging Simplex alarm system - which does point-to-point looped token ring <*cough*> on the alarm side.
What distances?
I'm trying to get them to confirm 50u will work point-to-point, but at some non-alarm-points there would be a necessary 50-to-62.5 exchange taking place and I'm not certain how to accomplish that (50->62.5 would likely have tolerable loss, but not 62.5->50).
I don't think changing core sizes in the middle would work even with SM optics.
On Wed, 14 Dec 2011, Keegan Holley wrote:
inappropriate. We are attempting to use Juniper single-mode SFPs (LX variety) across multi-mode fiber. Standard listed distance is always for SFPs using the appropriate type of fiber. Does anyone out there know how much distance we are likely to get? Thanks for your help in advance. Single mode just has a smaller core size for the smaller "beam" emitted by laser vs. LED. it works although I've never done it outside of a lab (MM is cheaper). As for the distance it theory that should come down to the optics and your transmit power. Hopefully this is just a cable connecting the router to a long line. I've never heard of a 10K MM fiber run since SX optics can't shoot that far. You should be able to get through the 500m or so that MM optics are rated for, but YMMV (errors, light levels, bounces, etc etc)
In a nutshell, don't do it if at all possible. This issue gets significantly worse at 10G. If there's any way to get SMF in place for this link, do it. In practice, you will likely get something less than the rated distance, particularly if the MM fiber in question is an older type, such as OM1. If you're using OM1, mode-conditioning jumpers at both ends are pretty much a must. The problems with shooting an LX/LH beam over MMF are threefold: 1. Attenuation on some flavors of MMF can be significantly higher than an equivalent run of SMF. 2. Modal dispersion on MMF will scatter and distort the LX beam, likely resulting in link errors because the receiver can't recover the data correctly. 3. Shooting a 9 micron beam into a 50 (or worse, 62.5) micron core, and getting enough of the beam to reach the 9 micron target at the other end to result in a recoverable signal is problematic. jms
2011/12/14 Justin M. Streiner <streiner@cluebyfour.org>
On Wed, 14 Dec 2011, Keegan Holley wrote:
inappropriate. We are attempting to use Juniper single-mode SFPs (LX
variety) across multi-mode fiber. Standard listed distance is always for SFPs using the appropriate type of fiber. Does anyone out there know how much distance we are likely to get? Thanks for your help in advance.
Single mode just has a smaller core size for the smaller "beam" emitted by laser vs. LED. it works although I've never done it outside of a lab (MM is cheaper). As for the distance it theory that should come down to the optics and your transmit power. Hopefully this is just a cable connecting the router to a long line. I've never heard of a 10K MM fiber run since SX optics can't shoot that far. You should be able to get through the 500m or so that MM optics are rated for, but YMMV (errors, light levels, bounces, etc etc)
In a nutshell, don't do it if at all possible. This issue gets significantly worse at 10G. If there's any way to get SMF in place for this link, do it.
+1 probably should have added that. I guess I just assumed.
In practice, you will likely get something less than the rated distance, particularly if the MM fiber in question is an older type, such as OM1. If you're using OM1, mode-conditioning jumpers at both ends are pretty much a must.
The problems with shooting an LX/LH beam over MMF are threefold: 1. Attenuation on some flavors of MMF can be significantly higher than an equivalent run of SMF.
+1 Assumed again..
2. Modal dispersion on MMF will scatter and distort the LX beam, likely resulting in link errors because the receiver can't recover the data correctly.
Not that I'm advocating this, but it's fine over short distances. I did this for a few lab routers where I wasn't concerned with link quality, but I was able to fill a 10G pipe with no errors/retransmit over about 10M.
3. Shooting a 9 micron beam into a 50 (or worse, 62.5) micron core, and getting enough of the beam to reach the 9 micron target at the other end to result in a recoverable signal is problematic.
Again for short distances it's doable. I agree not to even try over 62.5 though.
On 15/12/11 09:54, Justin M. Streiner wrote:
On Wed, 14 Dec 2011, Keegan Holley wrote:
inappropriate. We are attempting to use Juniper single-mode SFPs (LX variety) across multi-mode fiber. Standard listed distance is always for SFPs using the appropriate type of fiber. Does anyone out there know how much distance we are likely to get? Thanks for your help in advance. Single mode just has a smaller core size for the smaller "beam" emitted by laser vs. LED. it works although I've never done it outside of a lab (MM is cheaper). As for the distance it theory that should come down to the optics and your transmit power. Hopefully this is just a cable connecting the router to a long line. I've never heard of a 10K MM fiber run since SX optics can't shoot that far. You should be able to get through the 500m or so that MM optics are rated for, but YMMV (errors, light levels, bounces, etc etc)
In a nutshell, don't do it if at all possible. This issue gets significantly worse at 10G. If there's any way to get SMF in place for this link, do it.
In practice, you will likely get something less than the rated distance, particularly if the MM fiber in question is an older type, such as OM1. If you're using OM1, mode-conditioning jumpers at both ends are pretty much a must.
I sense confusion in the above. - LX drivers on MM fibre can work with Mode-Conditioning patch leads and can give you significant distance wins, particularly if you're using legacy OM1 Fibre. - SX drivers on SM fibre is not something i've ever seen done, I can't imagine why you'd do it - even if SX drivers are cheaper.
The problems with shooting an LX/LH beam over MMF are threefold: 1. Attenuation on some flavors of MMF can be significantly higher than an equivalent run of SMF. 2. Modal dispersion on MMF will scatter and distort the LX beam, likely resulting in link errors because the receiver can't recover the data correctly. 3. Shooting a 9 micron beam into a 50 (or worse, 62.5) micron core, and getting enough of the beam to reach the 9 micron target at the other end to result in a recoverable signal is problematic.
If you're not pushing your distance too far it'll probably be fine, to be honest. Back in the day when I was working on large legacy campus fibre runs, 220 metres was the max distance we considered OK for SX drivers and OM1 fibre (for gig ethernet). Mode conditioning leads would push this out to say, 900m trustworthy. If your distance is >900m I would suggest a fibre upgrade is on the cards. Again, the above all assumes mode-conditioning in use. If you're not mode-conditioning your effective range is going to be very short - to the point of unusability - and I'd be concerned about the affects of 'overdriving' fibre that is not set up for the use of low powered lasers and was instead optimised for LEDs, which obviously put out a lot less power. Mark.
participants (5)
-
Jeff Kell -
Justin M. Streiner -
Keegan Holley -
Mark Foster -
Marshall Eubanks