Hi.. Dear all.. thank you for your detailed explaination. Thank you very
much
I have another question when I doing my work
Our Sydney office face slowness to access the server in Ultrecht
The Connection is SYD01--> SIN01--> LON01-->LAMS089
yesterday I did a traceroute from SIN01 (100ms) SIN01-->LON01 (410ms) LON01
--> LAMS089 (420ms)
it is considered high, I called MCI world com to check the circuit, then
after they rerouted the circuit I checked again today
I did a traceroute from SIN01 router the round trip time to LON01 (270ms)
LON01 to LAMS089 (280MS)
But if I do traceroute from SYD01-->SIN01 (100ms) SIN01-->LON01 (410ms)
LON01 --> LAMS089 (420ms)
Why the time is difference?
-----Original Message-----
From: James Xie [mailto:[EMAIL PROTECTED]]
Sent: Friday, June 09, 2000 2:39 AM
To: Sim, CT (Chee Tong); 'Bartlett, DS1'; '[EMAIL PROTECTED]'
Subject: Re: telnet, ping, multicast and etc
At 05:37 PM 06/08/2000 +0800, Sim, CT (Chee Tong) wrote:
>Dear friends,
>
>Can I ask you some basic question, don't laugh at me :P if u just want to
>answer me one of the question, just help me .
>
>1) What is difference between ping and telnet? telnet is using port 23, how
>about PING? which port is that? I understand we can use the access-list
to
>control whether a telnet session can be established, how about ping, Are we
>using the ip route command to whether PING traffic to pass thru?
Telnet is an application using tcp port 23.
Ping is another application using icmp (a special ip protocol), neither TCP
nor UDP is
involved. Ping uses ICMP packet type echo.
>
>2) We open a port in Firewall to let user can telnet to a server in remote
>site. Does it mean that we can ping to the server. If not, What should we
>do in order to let user can ping to the server?
No, you have to open ICMP echo and echo-reply for ping to work.
>
>3) What is mean by Multicast? I know there is a range of IP for Multicast?
>But when we need it?
>
I think you are talking about layer 3 multicast. A special range of ip
address
224.0.0.0-239.0.0.0 are reserved for IP multicasting. For example, any
devices
configured with 224.0.0.5 are OSPF desinated routers. If you want to send
some
IP packets to those routers only, you can address the packet to that
address.
Multicast is also used for multimedia traffic. You can even use it across
the
Internet (MBONE). Multicast can be staticaly/dynaimcally routed. Popular
dynamic
routing protocols including IGMP, CGMP, PIM etc. AppleTalk also supports
multicasting.
Jim Xie
>
>Thanks
>
>Sim Chee Tong
>
>
>
>
>
>
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