SIP Myths

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Being in the temple of telecom all day every day, I’m sometimes dumbfounded to learn that people are still confused about SIP. I’ve provided six useful myth busters below.

1) SIP is Poor Quality.

SIP is a protocol that actually supports and enables higher quality communications than the traditional PSTN. However, like all tools, it can be used for evil instead of good. The poor quality issue is typically associated with running SIP over the public Internet. This is very common, but is subject to quality issues such as Jitter and latency which could reduce the quality of the conversation. SIP is often run on private or managed networks, many CLECs offer converged pipes that prioritize SIP traffic. There are lots of solutions, and SIP can be the means to improved HD quality conversations.

2) My old telephone system doesn’t support SIP, so I don’t need it.

SIP is a protocol. If you choose to connect this protocol to a device that does not support SIP then a gateway is required. Gateways are falling in price. Digium just announced new gateways starting at $1195. There are no shortage of SIP to PSTN gateway providers – AudioCodes, Sangoma, NET, InGate, and many more. Some of these devices have some security, increasingly the Session Border Controller (SBC) and SIP gateway are converging into a single device. For SBCs, consider Adtran, Sonus, Acme packet, and many more. Most of the big UC vendors offer integrated SBC and SIP support now including Avaya, Cisco, and Mitel. This stuff does not need to be expensive, and the savings associated with SIP (long distance, disaster recovery planning, and converged networking) will likely more than offset the initial costs of the equipment.

3) SIP is just for voice, and our network priorities are elsewhere. 

SIP is a protocol. It is used heavily in real time communications including voice, IM/presence, and video. It is also used directly to the endpoint, so softphones (desktop computers, smartphones, and tablets) can also use SIP as well as all the phones. The biggest mistake in SIP planning is not thinking big enough – it is growing exponentially because each user is multiplying the number of endpoints they use.

4) Interoperability is an Issue

Yes – however, it is a manageable issue that is actually getting smaller. SIP is a loose standard, meaning two implementations can be completely standards compliant and yet incompatible. SIP is as much as a standard as “Large” is on a T-Shirt. The good news is the vendors are working hard to self certify and that model is only practical if they can effectively agree on best practices. Look for things that support Polycom and Asterisk. The good news is your equipment is connected to the SIP provider in a compliant manner – for the most part the incompatibilities go away. That is the cloud is mostly compatible and not your problem. It’s the handoff to the endpoints and devices at the edge where problems arise. This is not nearly as much of a problem as it once was – particularly with a gateway in place.

5) We don’t have any SIP trunks, so we don’t have any SIP

SIP is a protocol. SIP does not require a SIP carrier. It is commonly implemented from call manager to phones even on a phone system without SIP trunks. It is also common between systems – say a call manager and a voice mail system. It is also frequently being used between sites – say between two call managers connected over an IP network. It is even possible to make a SIP call without a SIP trunk by dialing a SIP URI directly from the phone. Just like you don’t need email trunks to send email – it works over an IP network.  SIP trunks are primarily a means to convert SIP to PSTN.

6) I am suspicious of gifts, why does my carrier want me to switch to SIP if it reduces my monthly bill?

SIP services are inherently less expensive than TDM services. This is not a secret. For the most part, carriers are quiet about this and happy to charge for TDM – giving the customer what they wanted. It’s a dog eat dog world, and someone is going to pitch money savings associated with SIP, and the customer will eventually be lost if ignored.  Carriers are reluctantly now approaching their cash-cow customers and offering to help them save money by switching to SIP – it’s expensive, but so is losing the customer.

7) SIP is dangerous.

Yes, SIP can be dangerous, but over the years a simple set of precautionary guidelines have emerged that significantly reduces the chances of injury. SIP is very sharp and should be handled with gloves. All cabling carrying SIP should be reinforced with Teflon and Old Spice. Never raise your voice at SIP, and avoid direct eye contact. It knows what you are thinking. SIP multiplies with liquor (cant have just one sip), and always wear a condom.

There you have it, six useful myth busters.

Dave Michels