voip v ip telephony...

there is a difference...

in voip, traditional phone equipment such as analog phones, pbx's and pstn's,  are allowed to traverse ip networks via a voice capable router.  the router serves as the packetizer of the voice and signaling traffic, transporting it through the network

ip telephony works much the same way sending the traffic digitally, however, the ip telephony network includes ip capable end items, such as ip phones that use ethernet cabling for transit to the network...

phone registration...

using skinny (sccp) so far... see below:


r2620_01(config)#do sh ephone
ephone-1 Mac:000D.ED6C.308D TCP socket:[1] activeLine:0 REGISTERED in SCCP ver 1
1 and Server in ver 8
mediaActive:0 offhook:0 ringing:0 reset:0 reset_sent:0 paging 0 debug:0 caps:8
IP:172.16.50.1 50373 Telecaster 7940  keepalive 142 max_line 2
button 1: dn 1  number 1000 CH1   IDLE

ephone-2 Mac:000D.ED22.EB44 TCP socket:[2] activeLine:0 REGISTERED in SCCP ver 1
1 and Server in ver 8
mediaActive:0 offhook:0 ringing:0 reset:0 reset_sent:0 paging 0 debug:0 caps:8
IP:172.16.50.2 53077 Telecaster 7940  keepalive 137 max_line 2
button 2: dn 2  number 1001 CH1   IDLE
r2620_01(config)#

i tried downloading and using ccp but i didn't like it... like sdm it makes unnecessary changes to the configuration...

even telephony-service setup i don't like; i'd rather make my own decisions without being prompted

they mean it when they say the phones want to be in their own vlan... you can set up a tftp server on a pc or let the router do the work by uploading the phone system files into flash... the router can do the dhcp footwork.. in fact the voice router does just about everything...  i'm not thrilled that the phones are so externally dependant but i suppose that was cisco's way of designing it for enterprise use... i'd prefer to telnet into the damn phones and scrape configs into them... sip trunking is next... they're kind of a pain in the ass, truth be told...

phoneys...

there are three  ports on a given ip phone (at least on cisco phones)... they are serial (rs-232), switch and pc... the serial port is used for an expansion module, guess what the switch port is used for, guess what the pc port is used for?... so we know that the switch port will attach to the switch port on the phone and the pc port will attach from the phone to the pc...  how can this be since we know from our long hard studies in ccna universe that we can't carry multiple vlans across an access port, so that's it...  it's a trunk...  so use crossed cables for the devices and set up the switchport as a trunk...  actually, no...

the switchport is still configured as an access port, and the cables used are straight through... but we want to segregate the voice and data traffic, and how can we do that on an access port with a straight through cable...  what would father Odom say?

the phone is equipped with switch like hardware that allows it to receive and send tags...  the phone (switch) creates a trunk... this allows for data traffic (untagged) to be forwarded correctly while the voice vlan traffic is forwarded (tagged) with it's vlan...

an access port that supports vlans... shit...

100th post... voice

how fitting for my hundredth post to launch a new beginning... voice
(notes after cioara)

Voice

Ground is tip, positive, one wire; battery is ring, negative, other wire

On hook is open circuit; off hook is closed completing 48vdc circuit

Loop start signaling commences at off hook provided by CO (48vdc)

Glare happens when phone is picked up as a call comes in

Digitizing voice means changing analog signals into numbers

TDM (time division multiplexing) allows for networks to carry multiple conversations over a single 4 wire pair (numbers sent are divided by time)

T1 24 separate 64kbps channels known as a digital signal 0 (DS0)

Signaling – 2 types

CAS and CSS

Channel associated signaling – transmitted using the same bw as voice

Common channel signaling – transmitted using separate, dedicated channel

Q.931 is the most popular signaling protocol, which is used by ISDN

Uh oh, isdn never goes away…

Just as in life, those who do not pay heed to history are doomed to repeat it; pstn and pbx should be looked at…

Benefits of VOIP

Cisco loves comparisons

reduced communications cost

reduced cabling cost

seamless

reduced cost of moving the phone from a to b

unification – email, voicemail, fax

open standards (wait, did I just say open standard and cisco in the same breath)

quantization is how an analog signal is converted to a number 0-255 or +127 and -127

phone home...

posts on this coming soon...