[afnog] Connectivity to www.afrinic.net-BGP qtn

[Markus A. Wipfler]

Hi,

From your experience, what would be a good cableA to cableB ratio? If I have say X amount of bandwidth on cableA and  an average utilization of Y%?

Are there many providers who purchase 1 - 1 capacity (doubtful), or is there any rule of thumb that can be applied ?



Regards

--
Markus


On Jul 8, 2010, at 2:27 PM, Mark Tinka wrote:

> On Thursday 08 July 2010 06:00:10 pm Walubengo J wrote:
> 
>> ...and so just thinking in terms of engineering the
>> automatic backups systems for IP (or whatever) traffic
>> btwn TEAMs and SEACOM, would i be right in presuming the
>> following?
>> 
>> 1. that the Layer1 Circuitry btwn SEACOM and TEAMS should
>> be in place & then 2. that ISP/IBP connecting into both
>> fibers (Layer2?) then have to enter an interconnection
>> agreement as well as connect IP routers btwn them?
>> 
>> walu.
>> nb: still think step 1 not necessary though since step2
>> alone could provide the redundancy sort...
> 
> The bottom line is this:
> 
> 	- Submarine operators along the same path normally have no
> 	  incentive to interconnect with each other on the on-set,
> 	  as they are competitors.
> 
> 	- Those that interconnect would do so at an aggregate
> 	  level, i.e., between SEACOM and TEAMS, not between
> 	  SEACOM's customers and TEAMS' customers, which means just
> 	  because there is an interconnect, doesn't mean you will
> 	  enjoy it when there is a failure on your favorite cable
> 	  system.
> 
> 	- Circuit-switched networks are not very efficient, as
> 	  paths need to be pre-provisioned before they can be used,
> 	  and remain that way regardless of whether you use them or
> 	  not. So even if there's an interconnect between SEACOM
> 	  and TEAMS, it might not have anything to do with the path
> 	  you're interested in at the time of failure.
> 
> 	- Multiple cable operators are NOT obligated to
> 	  interconnect with each other (again, especially if
> 	  they're direct competitors in a given market).
> 
> 	- Automated switchovers at the Layer 1 level have been
> 	  spec'd, but haven't really worked out reliably in the
> 	  real world, e.g., APS (Automatic Protection Switching),
> 	  a.k.a 1+1, involves buying one "live" path and one
> 	  "protect" path on a single cable system. If the live path
> 	  fails, APS switches traffic over to the protect path.
> 	  Although this mechanism is well-documented, it is always
> 	  cheaper to buy one linear (linear = unprotected) service
> 	  from Provider A and another linear service from Provider
> 	  B and implement your own redundancy at the IP layer using
> 	  your IGP and BGP. No point in paying for APS, as you're
> 	  losing money on a circuit on which you can't put
> 	  bandwidth half the time.
> 
> 	- Cable operators generally have no interest in the
> 	  payload, so they won't build their networks around what
> 	  you plan to run on them. The issue of application
> 	  resiliency is left up to the user.
> 
> 	- ISP's are fully responsible for mitigating their risk re:
> 	  circuit failure. Have diverse paths, have sufficient
> 	  bandwidth along those paths. Don't rely on the Layer 1
> 	  provider for redundancy.
> 
> Hope this helps.
> 
> Cheers,
> 
> Mark.
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