Black-Box Testing Fring for SIP and SkypeOut


”Fring” is a Instant Messaging and VoIP client for the iPod and iPhone Touch. It’s a free download, and I decided to try it.

Fring Setup

When you start Fring, you have to register for a Fring User ID — before you even enter your IM, SIP, or Skype contact info. That suggested to me that it was doing this stuff through a central server.

I setup my MSN, AOL, and Yahoo IM contacts and sent a few IMs. It sets your IM status to “Mobile with Fring”.

Configuring VoIP

Then I setup my Skype account. I bought some SkypeOut credit. But I was never able to get it to place a call outbound. I deleted my Skype login on Fring, then tried to set it up again — but it wouldn’t let me login.

I also configured a SIP account with a VoIP carrier, Vwave.net, an NGTelecom Company. NGTelecom is a sister company; they’re a very modern SIP VoIP provider: they have an Acme Packet SBC and DNS SRV records. I entered my SIP username, SIP authentication password, and the Vwave domain, “vwave.net”.

The Fring system did a proper DNS SRV lookup, then registered through the NGTelecom Acme Packet SBC. I noticed that it registered from 63.215.199.71, an IP address assigned to CWIE, LLC of Tempe, AZ.

The CWIE IP Address did not stay registered after I left the Fring application on my iPod Touch. In fact, when I restarted Fring, it wasn’t always able to re-register; the progress spinner would keep on spinning.

Call Quality Problems

While Fring was registered, I placed several (maybe 6) calls. Two (2) of them carried intelligible speech. In a couple of cases, I heard weird feedback, on my iPod Touch, before the call was even connected. But I don’t know of any similar examples from The Cisco “Duck Quack” page of Voice Quality Symptoms. In some of the call cases, I had one way audio. (Vwave’s Acme Packet SBC generally solves all NAT problems for moderately-well-behaved SIP clients, but symmetric RTP is required if the RTP flows through a NAT device or stateful firewall.)

Comments and Conclusions

I was hoping for a SIP client that actually runs on the iPod Touch. Fring apparently sends the call across the Internet, so that means your SIP proxy has to be reachable from the Internet.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s