From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Tue Aug 09 2005 - 17:04:22 GMT-3
There are different types of IPv4 address assignments.
Provider-based addressing is when you get an IPv4 block assigned from
your specific ISP. Typically BGP is not required in cases like this
since you do not need to announce the ISPs address space back to them.
With this design if you change providers you must change addressing.
Other address blocks are known as "portable" addresses or
"provider independent" addresses. These blocks assigned to your network
directly through agencies such as ARIN or APNIC. This address space is
then announced to your provider(s) via BGP. Since you "own" this
address space you ultimately determine how it is routed throughout the
network.
The reason why I said that "Most ISPs will not allow you to
announce another ISPs address space." has to do with how peering and
transit agreements are setup. For example suppose you have links to ISP
A and ISP B, but your address space belongs to ISP A. By announcing ISP
A's address space to ISP B, ISP B is providing transit to ISP A (which
is essentially you) free of charge. Policies will vary from provider to
provider but typically the bigger the ISP is the more strict their
policies will be.
Check here for more info:
http://www.apnic.net/meetings/12/docs/proposal-multihome-assign.html
http://www.ripe.net/ripe/meetings/ripe-39/presentations/aspolicy/
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
24/7 Support: http://forum.internetworkexpert.com
Live Chat: http://www.internetworkexpert.com/chat/
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Vazman
> Sent: Tuesday, August 09, 2005 10:56 AM
> To: Jens Petter Eikeland
> Cc: Helena Qiu; ccielab@groupstudy.com
> Subject: Re: is it possible to use private AS# peering with 2 ISPs?
>
> Brian,
>
> In reference to your statement.
>
> "Most ISPs will not allow you to announce another ISPs address space."
>
> How would you go about setting up Internet connectivity with 2
> different ISP's (for diversity) and use the same address space? Just
> curious.
>
> Thanks.
>
> On 8/9/05, Jens Petter Eikeland <jenseike@start.no> wrote:
> > Hi ,
> >
> > The isp will filter out that privat as, so you should be good
> >
> > Jens Petter Eikeland
> >
> > -----Opprinnelig melding-----
> > Fra: nobody@groupstudy.com [mailto:nobody@groupstudy.com] Pe vegne
av
> Helena
> > Qiu
> > Sendt: 9. august 2005 16:58
> > Til: ccielab@groupstudy.com
> > Emne: is it possible to use private AS# peering with 2 ISPs?
> >
> > Dear all,
> >
> > We are using ISP A's service. ISP A assigned ip range and private AS
> number
> > to us. For the backup purpose, we are going to use ISP B as well. We
are
> > going to keep our IP range and private AS # assigned by ISP A. Is it
> > possible for us to use this private AS# to peer with ISP B?
> >
> > Please advise. Thanks.
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Tired of spam? Yahoo! Mail has the best spam protection around
> > http://mail.yahoo.com
> >
> >
This archive was generated by hypermail 2.1.4 : Sun Sep 04 2005 - 17:01:18 GMT-3