Question:
How do you make a display filter that filters out most RTP frames, but leaves a representative sample? Sometimes it's convenient to see a sampling of RTP frames in Wireshark, without having to see 50 per second.
Answer:
Rather then see 50 frames per second for every RTP flow, how about one frame every 5 seconds?
Wireshark display filter:
rtp[3:1]==0 or rtp.marker==1...
When you're connecting to the rest of the world to make and receive phone calls, you have several design options available. Or, more precisely, your Voice Service Providers have many options available.
VoIP via Layer-3 VPN
In this case, a Layer-3 VPN, such as MPLS over the Voice Provider’s own equipment, is used to connect a Voice customer to the Voice service provider. Shared infrastructure i...
The BroadSoft BroadWorks DBS is a different animal than other BroadWorks servers, and it requires a special set of commands to keep it alive and well. The level of care and feeding required for the database reminds of BroadWorks App Server release R12 and R13; those were not happy days.
Check status of the FRA Disk Group
dbsctl diskinfo
/etc/init.d/oracleasm listdisks
On a healthy, normal sys...
"Network Neutrality" advocates teach us that banning certain Active Queue Management (AQM) algorithms will result in greater freedom on the Internet. For example: Barack Obama wants to ban "Paid Prioritization," which Cisco calls "Low Latency Queueing".
Even folks interested in computers, but who don't build or run networks, seem to have some downright strange opinions. For example, when Net...
The Cisco Small Business SPA-500 series phones (such as the SPA-502G, SPA-508G) include a Cisco-signed SSL certificate. Until very recently, all of the Cisco SPA-500-series phones shipped were signed by a Sipura certificate. Sipura was the Korean company that was bought by Linksys before Linksys was bought by Cisco.
Sometime after August 2013, Cisco Small Business started shipping phones sig...
When it comes to telephones, everybody has certain expectations.
Nobody wants a phone that fails occasionally. And most service providers have a model of phone that they trust; nobody wants to try out a new SIP phone and learn that it fails in an obscure, but important feature.
For example: Have you seen the new Yealinks? Or what about the improved Grandstreams? How do you ensure the phone is...
BroadWorks calls it "URL Dialing": calling from your hosted PBX VoIP phone or SIP Trunking device to a random SIP URI. Lately, Polycom has been handing out SIP URIs and inviting people to test out their video bridges. Let's say you want to call to sip:1234@opensips.org -- how should it work?
Most VoIP services providers -- such as those built on BroadWorks and Metaswitch -- don't allow calls fr...
Metaswitch and Oracle Communications (formerly Acme Packet) would love to own each other's customers; and many service providers own both.
This design shows how the two can be combined to make a scalable, high-performance SIP termination platform appropriate for outbound call centers.
High-performance call termination can be a challenge; many conventional systems, rich in SIP trunking feat...
1. Introduction
Customers want quality voice and video. This can be readily provided using engineered links -- i.e., paths that prioritize, reserve, or otherwise guarantee that the real-time voice and video packets will be delivered within the required timing constraints. But because of the wonderful cost reductions of Internet bandwidth, customers would prefer to get the quality voice and vide...
Two of my favorite companies, BroadSoft and Metaswitch, are showing that they're interested in the other guy's turf.
At the recent Metaswitch Forum in New Orleans, the talk was about the "NFV" standard for managing telecom software, and about Business Services. Metaswitch's customer base -- independent telcos -- has long been strong in TDM voice (PRI, CAS T1) residential (analog service via GR-...
I started my current job on the US Memorial Day, 2003.
In 2003:
The Cisco 7960 was the Cadillac VoIP Phone. (Cisco appears to have stopped supporting the SIP stack on the Cisco 7900 series phone.) Polycom's SoundPoint IP phones came from behind, and are clearly the dominant phones in the industry.
The only robust way to deliver "Digital Voice" service over a Cable Company's HFC n...
At the SIP Forum’s SIPNOC 2013 meeting in Herndon Virginia, I'll be presenting on how to kill VoIP Theft. Is it more like a Werewolf, or more like a Hydra?
The Bad Guys are stealing service from any VoIP service provider they can. The attacks come through several vectors, but typically they (a) discover SIP credentials, then do direct SIP registration; or (b) compromise a customer VoIP devic...
At the SIP Forum’s SIPNOC 2013 event in Herndon, Virginia, April 22-25 2013, Mark Lindsey from ECG will be explaining how VoIP Service Providers can engineer less to build better customer deployments.
Engineers live to build things, and solve new problems. But if every customer becomes an opportunity to design afresh, then no two customers will be alike. The service provider that prides itse...
In telecom, the "demarc" represents the point in the network where the responsibility differs; it is the interface between the service provider and the customer.
Traditional Analog POTS: The Demarc is often a test port on the side of the building. If something is broken between the test port and the customer's phone, then it's the customer's responsibility to fix it. Otherwise, it's the servic...
The Sonoran Desert: Location of the BroadSoft Connections Conferences for 10 years.
I'm involved in the maintenance of a Call Control Client for BroadWorks, Attaché, and a Provisioning Library for BroadWorks, Alpaca. This makes me very interested in changes BroadSoft makes to their interfaces.
At present, BroadSoft supports a number of interfaces:
OCI-P for Provisioning
OCI-C for Call Control...
Mark Lindsey