[j-nsp] Independent /32s for Interfaces - anybody doing that?

[v]

Now I understand - thank you very much for your explanations!

Am 2016-05-31 um 13:31 schrieb Vincent Bernat:
>   ❦ 31 mai 2016 13:12 CEST, v <vekt0r7 at gmx.net> :
>
>> I just read about using independent /32 addresses for interfaces and I
>> would like to know whether anybody uses that. Found the following
>> information about such a configuration:
>> -This means that there is no relation between the addresses on the two ends of an interface
>> -This relies on the IGP to provide this relationship
>> -This significantly reduces the burden of address management and synchronization
>> -Also, reconfiguration of topology is much easier
>>
>> Are there more pros and cons than that?
>> Does anyone have experience with such a configuration?
> Hi!
>
> I believe that you are talking about unnumbered interfaces: you put a
> /32 on a loopback and you tell other interfaces to use the loopback
> address. For example:
>
> interfaces {
>      lo0 {
>          unit 1 {
>              family inet {
>                  address 203.0.113.3/32;
>              }
>          }
>      }
>      ge-0/0/1 {
>          unit 0 {
>              family inet {
>                  unnumbered-address lo0.1;
>              }
>          }
>      }
>      ge-0/0/2 {
>          unit 0 {
>              family inet {
>                  unnumbered-address lo0.1;
>              }
>          }
>      }
> }
>
> I find this scheme very convienent:
>
>   1. You can use only one public IP address for the whole equipment.
>
>   2. You have less configuration to do and this is less error-prone. An
>      IGP like OSPF would make each router discover the addresses of all
>      other routers automatically.
>
> Unfortunately, the support vary widely accross vendors. I believe the
> support is pretty good with Cisco. With Juniper, it really depends on
> the equipment. The MX has pretty good support, but has some limitations
> (for example, static BFD + unnumbered doesn't work). The QFX doesn't
> support unnumbered interfaces in various places (like for example, on an
> IRB interface). From what I have been told, Juniper has no plan to fix
> that. Cumulus supports them too (but I can't testify on the completeness
> of the support). Other vendors may have no support at all for this, so
> you get into some kind of vendor-lockin if you rely on this.