[Sip] Question about hostname's BNF definition

[Lei Yu <yulei_pku@yahoo.com>]

Hi, Everyone, 
I have 2 questions related to BNF definition for 
hostname. Here is the part from RFC3261: 
" 
hostname = *( domainlabel "." ) toplabel [ "." ] 
domainlabel = alphanum 
/ alphanum *( alphanum / "-" ) alphanum 
toplabel = ALPHA / ALPHA *( alphanum / "-" ) alphanum 
" 
And here are my 2 questions: 
(1). Based on the BNF definition for hostname, 
a "." at the end is legal which means the following 
string is a legal hostname: 
"company.com." 
This is wrong, right? No "." should be allowed 
at the end of hostname. 
(2). Based on the different definition for 
domainlable and toplable, toplable does not alow 
token starts with DIGIT. Why is that? 


Thanks. 

Lei Yu 
Software Engineer 
Motorola

---

Do you Yahoo!?
HotJobs - Search new jobs daily now