Subject: RESEND: Last call on LSP Ping

From: "David Allan" <[email-masked]>
Date: Sun, 8 Dec 2002 12:12:52 -0500

Still finding my way around a different e-mail system....

Curtis: 

Your tone suggests that you think this document is ready for publication,
and the objections that have been raised are purely designed to obstruct
progress, is this true?

cheers 
Dave 
-----Original Message----- 
From: Curtis Villamizar [mailto:[email-masked]] 
Sent: Saturday, December 07, 2002 6:52 PM 
To: [email-masked] 
Cc: [email-masked]; [email-masked]; [email-masked] 
Subject: Re: Last call on LSP Ping 

In message
<[email-masked] 
host.net>, [email-masked] writes: 
> > > George....I think the point Shahram was making it is not 
> > even allowed 
> > > outside the host/source box according to the text quoted 
> > from the RFcs 
> > > below.  Wrapping it in some other package (any, not just 
> > MPLS) is still 
> > > violating this requirement...and note that it *must* be 
> > placed in some 
> > > package to get across any tranmission medium....IP pkts 
> > don't go raw on 
> > > wires. 
> > 
> > As far as I'm concerned it is within the spirit of the RFCs.  If you 
> > want to insist on the letter of the law, perhaps you should look into 
> > a career as a solicitor. 
> > 
> > ...George 
> 
> George, I am asking a serious question here and I would have appreciated a

> serious answer please.  I'd also like to see some responses to the other 
> issues that have been raised.  My experience to date suggests one only
gets 
> responses 'when it suits'.  At least others (esp Erics R and G and Curtis)

> have attempted to provide reasoned answers. 
> 
> This stuff is going to get delivered whatever right?....so I want to be
sure 
> that its as fit for purpose as possible (and that's more than this 
> particular 127/8 point). 
A lot of packets from my site (here at home) go through the Internet, 
all destined to a subnet of 10/8 (in the office).  This (10/8) is also 
not a routeable address covered in the same sections as 127/8 in 
RFC1700 and RFC1812.  Its OK to deliver these packets since they are 
encapsulated in something else.  It is not considered a violation of 
RFC1700 or RFC1812 to forward these across the Internet where 10/8 and 
127/8 are considered to be "martian packets". 
Going way back to 1992, the mbone tunnels were originally built out of 
source routed tunnels with a multicast destination.  They later 
switched to a tunnelled encapsulation due to performance problems of 
certain routers when handling large volumes of source routed packets. 
This was not considered a violation of RFC1700 or RFC1812. 
There are plenty of precedences for using private addresses inside 
something else. 
In many circumstances, packets with private addresses are tunneled. 
You have to separately look at what happens at the end of the tunnel 
after the encapsulation is stripped off. 
> Here's my understanding of the current position on this specific point: 
> 
> There are (at least) 2 possible cases: 
> 1     127/8 addressed pkts should never leave a box 
> 2     127/8 can always leave a box.....since I can put 127/8 addressed 
> pkts in ATM or FR (or ethernet?) directly.....I see no significant
technical 
> difference here to the MPLS case that is argued as being justified. 
> [Aside - one could generalise the above case 2 to *any* IP addressed
packet, 
> or we could make 127/8 a special case] 
127/8 cannot be forwarded based on the 127/8 destination.  Just as 
traffic from 10/8 can leave a subnet, croos the big-I Internet, and 
reenter a subnet of 10/8, so can a packet be formed with a 127/8 
destination and be encapsulated in something and sent. 
What happens when the outside encapsulation is stripped off also has 
to be examined. 
When the labels are gone, the 127/8 remains and the packet is sent to 
the loopback address.  That is the one exception allowed by RFC1812 
and delivery to the loopback is the explicit intended use of 127/8. 
> Now I just want a ruling that 2 is fine (perhaps as a special case?), and
as 
> long as its agreed now then that's OK....I don't want this raised by
someone 
> X months hence after this stuff is being shipped and operators have
deployed 
> it. 
If you had a legitimate reason to deliver traffic to the loopback 
device on the other end of a FR or ATM link, then putting 127.0.0.1 in 
the destination and a valid UDP payload with a port number for that 
application, then it would be fine. 
There is a legitimate reason for selecting a 127/8 address for this 
application.  Because it is used for a diagnostic we DON"T want it to 
be routeable.  RFC1700 and RFC1812 guarentee that it won't be 
routeable.  RFC1700 and RFC1812 explicitly set this address space 
aside for use with the loopback device. 
> regards, Neil 
Once again, I think the MPLS-ping objectors are simply grasping at 
straws. 
Curtis

---

From: Curtis Villamizar <[email-masked]>
Date: Sun, 08 Dec 2002 14:35:42 -0500

In message <[email-masked]>, "
> and the objections that have been raised are purely designed to obstruct

Oops ... I guess I shouldn't have replied to the list then.

Curtis