If you have an ISP assigned address that you are using, can you advertise
that address out to another ISP?? Or if you want redundancy do you have to
get your own registered IP range and then BGP advertise that through two
ISPs?
>
>
>See comments below:
>
> > I haven't worked with BGP yet, so someone please correct me if I'm wrong
> > with this -
> >
> > My understanding is that even if you have internet connections to two
> > differnet ISPs, you don't have to BGP. If you are using IP addresses
>they
> > have assigned to you then you are ok.
>It depends what "ok" means for you. If you need redundancy and backup,
>then you are not "ok". Consider the scenario below :
>
>|-------| |-----------| |-------|
>| ISP1 |---------------| Customer |-----------| ISP2 |
>| | | | | |
>| AS1 | | | | AS2 |
>|-------| |-----------| |-------|
>
>The customer is multihomed to AS1 and AS2. The customer is not running BGP
>in this scenario.
>
>Suppose ISP1 has assigned the customer 10.10.10.0/24 and ISP2 has
>assigned the customer 10.10.11.0/24. Both ISPs are statically routing
>those blocks to the customer. The customer has two default routes, one to
>each ISP (he could prefer one ISP or the other for outbound traffic but
>inbound traffic will come from ISP1 or ISP2 depending on the destination
>ip address).
>
>Inbound traffic destined for hosts in 10.10.10.0/24 comes through ISP1 as
>ISP1 is originating and advertising this block. Inbound traffic destined
>for hosts in 10.10.11.0/24 comes through ISP2 as ISP2 is originating and
>advertising this block.
>
>Now what happens if the connection between the customer and ISP1 goes down
>for any reason ? Well you will see that hosts in 10.10.10.0/24 will be
>unreachable from outside the customer's network. So redundancy is not
>achieved properly as half of the customer's network will be down.
>
>
> > The big reason to use BGP would be if you have a block of registered IP
> > addresses and you want to advertise them to the internet via two
>different
> > ISPs.
>I would say that as soon as you are multihomed (to 2 different providers)
>then using BGP is a Must. (Of course if you really want total redundancy
>and the option to do intelligent routing, load-sharing..).
>
>
> >
> >
> > >
> > >Hellow group!!
> > >According to cisco press book, when company has two connections active
>to
> > >two different ISPs, BGP should be used.
> > >Could anybody tell me what is the result of connecting two active
> > >connections to two different ISPs?
> > >I know that one connection should be used as a backup line only while
>the
> > >other is active in order not to use BGP.
> > >Thanks in advance.
> > >
> > >........................................................
> > >iWon.com http://www.iwon.com why wouldn't you?
> > >........................................................
> > >
> > >___________________________________
> > >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
> > >FAQ, list archives, and subscription info: http://www.groupstudy.com
> > >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
> >
> > ________________________________________________________________________
> > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
> >
> > ___________________________________
> > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
> > FAQ, list archives, and subscription info: http://www.groupstudy.com
> > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
> >
>
>--
>Contrary to popular belief, Unix IS user friendly. It just happens
>to be very selective about who it decides to make friends with.
>
>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
>Andre Riscalla Network Specialist - Internet
>[EMAIL PROTECTED] 514-940-5664
>Network Engineering AT&T Canada
>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
>
>___________________________________
>UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
>FAQ, list archives, and subscription info: http://www.groupstudy.com
>Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
