[ih] TTL [was Exterior Gateway Protocol]

[Guy Almes]

Brian,
   It did give us traceroute.  Not quite saving the Internet, but it was 
wonderful,
	-- Guy

On 9/4/20 7:05 PM, Brian E Carpenter via Internet-history wrote:
> So, here's another history question:
> 
> On 05-Sep-20 05:11, Tony Li via Internet-history wrote:
> ...
>> Topology.
>>
>> Strictly speaking, AS-level routing is not necessary. You can do everything with other protocols and leaking/redistribution except that:
>>
>> - No protocol other than BGP can support Internet (or service provider) route scale.
>>
>> - Leaking/redistribution has no loop prevention mechanism.
> 
> I was taught many years ago that the TTL field (renamed Hop Limit in IPv6) was intended only as a last resort method of loop prevention.
> 
> a) Is that accurate?
> b) Has it ever saved the Internet?
> 
> (It does have one slightly bizarre use today: check that it's still 255 to detect forwarded link-local packets, and there's also RFC5082.)
> 
>      Brian
>