Hi Margaret,
Here is the description of NEC IX router.
>> NEC IX router is the only implementation supporting this, as far as
>> i know (i'm a bit embarrassed, KAME doesn't handle this - yet).
>
>Does the NEC implementation use multi-instance routing protocols? Do you
>know anyone
>on this team? Could we get them to describe how they handle the site
>border router case
>in detail?
>
>I am very interested in understanding how this works.
Let me describe how sites are defined in IX router using diagram below, first.
This router has 8 logical interfaces.
By default, all logical interfaces belong to a site called "default_site".
Therefore, with this default site configuration, the router will not work as
SBR. All site-local address will be routed to any other logical interfaces
based on a routing table.
With this configuration, RIPng, OSPFv3 will propagate routing entries
for site-local prefixes. Currently, our implementation of BGP4+ does
not handle site-local prefixes. Also, we don't have IS-IS on IX routers, yet.
|
|
+--------+--------+
| if1 |
| |
-------|if4 if2|-------
| |
| if3 |
+---+----+--------+
|
|
Default Site Configuration (NOT SBR)
------------------------------------
To create sites (to configure a router as SBR),
* 1st, define site-name. eg. my_site.
* add logical interfaces to "my_site".
eg. add if1 and if2 to "my_site.
At this point, the router has 2 sites and acts as ABR.
"default_site" has if3 and if4.
"my_site" has if1 and if2.
So any packets destined to site-local addresses will never
forwarded across sites.
Site Boundary
| /
(my_site) | /
+--------+--------+
| if4 / |
| / |
-------|if3 / if1|-------
| / |
| / if2 |
+-/-+----+--------+ (default_site)
/ |
/ |
SBR Configuration w/ 2 Sites
----------------------------
Now, to run RIPng on this router, simply enable RIPng on each interfaces.
Single RIPng process is running on this router. Global prefixes will be
propagated to all interfaces; however, site-local prefix will be propagated
only to interfaces belongs to the same site.
eg. fec0:0:0:100::/64 from if1 will be propagated to if2, but not to
neither if3 nor if4.
Now, OSPFv3. Since it is much complicated than any RIPng, of course,
and it has capability to run multiple processes by nature, we decided to
run an OSPFv3 process per site. Still, we could have handle site routing
with single OSPFv3 process. Complication is the most dominant factor in our
decision. For example, what if someone is sending an Intra-Area-Prefix-LSA
which contains both global and site-local prefixes. Receiving OSPFv3 router
might need to decompose LSA into two LSAs which contain global and site-local
separately. BUT, this is not allowed. I believe that we need to make
agreements on this point.
One of our concerns on multi-process implementation is that
global prefixes need to be redistributed among OSPFv3 process once
sites are defined.
Also, IX router's PIM-SM for IPv6 is capable of sites.
Would this be of help?
----
Hiroki Ishibashi
[EMAIL PROTECTED]
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