network resources

Welsh, Armand armand.welsh at sscims.com
Tue Dec 19 17:16:21 GMT 2000


-> -----Original Message-----
-> From: Charles Crawford [mailto:ccrawford at atsengineers.com]
-> Sent: Tuesday, December 19, 2000 8:50 AM
-> To: Welsh, Armand; Samba Listserve (E-mail)
-> Cc: Samba-Ntdom Listserve (E-mail); Samba-Technical 
-> Listserve (E-mail)
-> Subject: RE: network resources
-> 
-> 
-> WINS/DNS enables one to ping by hostname. The response time 
-> is irrelevant if
-> the machine cannot locate the host.

Correct, this occurs only once durring a ping process.

-> When I say the response time is doubled, I mean the total 
-> round-trip time,
-> not the time it took for the machine being pinged to respond 
-> to the ping
-> request.

the round trip time, also known as latency, as reported by 
the ping utility, does not include, in any way, the name 
resolution process.  The name lookup is only performed once 
per ping command; prior to precessing the ping packets.  Arp 
lookups, however, do occur on each and every ping packet sent.  

You can test this, by pinging by host name, then pinging by 
ip address.  The latency diffences should be neglegable.


-> The NIC's are fine, and so are the Cisco Switches. The 
-> problem appears to be
-> an issue of how NT and Samba/Linux interact with each other. 
-> The response
-> time being doubled indicates to me that the traffic is 
-> traveling twice the
-> distance, not being held up somewhere... BTW, it is EXACTLY 
-> twice the time,
-> so I think that that indicates an extra trip for each 
-> packet to the
-> destination machine.

run a traceroute from the client to the host, both by ip 
address, and by host name, you will be able to see the results.





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