Kudos from a lurker.. I have been reading this list for years and have to give thanx to those in this conversation. I don't remember having felt like I had learned the basics about something I have no experience with as well from any previous conversations...
Larry Puckette Network Analyst Temple Inland [EMAIL PROTECTED] 512/434-1838 Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety. Benjamin Franklin, 1759 -----Original Message----- From: Bruce Enders [mailto:benders@;netcraftsmen.net] Sent: Thursday, October 17, 2002 7:02 AM To: [EMAIL PROTECTED] Subject: Re: VoIP Clarification. [7:55682] Priscilla, Thanks. High praise considering the source. ;-) The reason the telephone number is mapped to the MAC is so that the number follows the DEVICE on the network. Please note that I stated that the IP phone "identified" itself to the CM by announcing its MAC address. If you leave Extension Mobility out of the equation, it is a pretty ironclad way to guarantee that the phone number assigned to the phone will be consistent even if the phone moves to a new network segment, ANY network segment that can route IP traffic to the CallManager. Bruce Priscilla Oppenheimer wrote: Great answer. Finally an explanation that makes sense for the marketing babble about IP Telephony making Moves, Adds, and Changes easier. ;-) One quesiton though, does CallManager really care about MAC addresses? Unless the receiving phone is on the same network segment as the calling phone, the MAC address won't help matters. ARP would take care of getting the MAC when it's needed. Priscilla Bruce Enders wrote: B. J. The only trick here is to remember that the User phone number "1111" is "mapped" to the MAC address and IP address of the ethernet interface associated with the hard phone, or the laptop in the case of Softphone. (Both are PCs running specific applications software). Whenever either is disconnected from the network long enough for link to drop, they have to check in with DHCP when they are re-connected to the network. Both also have to check in with their CallManager. During that process, they identify themselves using their MAC address, and announce their current IP address. After that, the CM can simply forward based on the IP address. This capability is one of the primary reasons that Moves, Adds, and Changes in an IP Telephony system are far more simple than in a legacy PBX environment. (The logic behind your response sounds like it comes from the legacy telephone world, which is very used to working in a very static addressing environment). Bruce B.J. Wilson wrote: Hi Vance - I too am studying All Things VoIP, and I'm curious how this would work. Say you have User A trying to call User B. User B is currently in the office. So User A dials '1111' which is User B's phone number (or "route pattern" if you want to be specific). CallManager picks up the route pattern, looks up User B's location, and forwards the call on. All is good. Now, say User B is telecommuting. How does CallManager know this? How does your RAS (remote access) server notify CM that User B's geographical location has moved? Is there something in User B's RAS (Registration, Admission and Status) setup that alerts CM to the fact that they're dialing in from home? Thanks, BJ ----- Original Message ----- From: "Vance Krier" To: Sent: Wednesday, October 16, 2002 4:08 AM Subject: Re: VoIP Clarification. [7:55682] Hey Stu, In simple terms, yes you are correct. However, as I'm sure you know, you need to take this type of setup with a grain of salt. If you have a decent bandwidth, low latency, consistent connection between the phone and CM, it works fine. There's absolutely no guarantees for QoS on the Internet. Now, FWIW, I use softphone on my laptop when I travel and I've gotten satisfactory results (IMO) better than 75% of the time. I always pitch this as being a *kewl* feature, but never as a selling point. I'm very, very cautious with customers over this. As long as the user using it is understanding and realizes there will be times when it doesn't work or the quality is really crappy, then typically they stay happy. Not something I'd give to Internet/computer/technology illiterate executive. I love it, by the way. Good luck, Vance ""Stuart Pittwood"" wrote in message news:200210160746.HAA10542@;groupstudy.com ... Good Morning all, I am just starting to look into VoIP as I have been asked by my manager to do some research and find out if there are any benifits from VoIP for our firm. Am I right in saying that if we had a solution based on Cat 6000 (or similar) switches, with a cisco VPN solution for the home workers, that users who use their laptop at home with cisco softphone or hardware phone could have their telephone extenstion follow them? Please forgive the simplicity of my question, just making sure I am thinking along the right lines. Thanks Stu -- Bruce Enders Email: [EMAIL PROTECTED] Chesapeake NetCraftsmen o:(410)-280-6927, c:(443)-994-0678 1290 Bay Dale Drive, Suite 312 WWW: http://www.netcraftsmen.net Arnold, MD 21012-2325 Cisco CCSI# 96047 Efax 443-331-0651 -- Bruce Enders Email: [EMAIL PROTECTED] Chesapeake NetCraftsmen o:(410)-280-6927, c:(443)-994-0678 1290 Bay Dale Drive, Suite 312 WWW: http://www.netcraftsmen.net Arnold, MD 21012-2325 Cisco CCSI# 96047 Efax 443-331-0651 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=55801&t=55801 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
