The Covid-19 pandemic caused an worldwide cause for concern. The best way to contain it is to reduce people direct interaction.
Some governments already imposed travel bans, forbid crowded events and closing schools.
Companies also limited travelling and ultimately send people to home office.
This is a great case scenario for companies to have the right UCC solution in place.
People can still collaborate, arrange meetings on the ‘safety’ of their home without the risks of public transport travelling, office doors knobs, next desk colleague or customer meetings.
Now, Skype for Business and others become a critical tool for companies.
But there is a ‘unexpected catch’ for companies to send half or more of their workers home: How do workers access the company internal resources? usually using a VPN.
Suddenly, companies have a large number of people using the internet speed and bandwidth to fighting for access to the systems (and also the Internet) -and it’s probably not the 1Gpbs per user as on the office LAN –
Now this old feature topic raised again.
Besides the issue of available bandwidth (including the one at home), how this can this get worth?
Some companies have VPN policies (either to security reasons or simplified administration) to enforce all their managed PC to send all the traffic throw the VPN (let’s call it ‘Forced-tunnel VPN’).
This includes applications traffic, emails, files, internet browsing including video content and… Skype for Business (SfB)!
As you already imagine people expect audio, video and the shared contents to be real-time but the SfB client is competing with:
- Other applications loading files, email, video from the same tunnel
- Double encryption/decryption: SfB encrypts his traffic and the VPN encrypt the traffic that is sent over the internet
If not well planned or prepared, IT support is going to have a flood of disgruntled users complaining about voice quality issues, failures, and unsuccessful meetings.
‘Force-tunnel VPN’ creates an additional problem for real-time protocols. Instead of delivering the packets to the shortest route possible, it will take a very long path in some cases. Let’s use the following picture to show you that:
There are two evident situations:
- The calls between two home office worker of the same company will go first to the VPN server. And the call might get encrypted/decrypted twice
- If another ‘SfB enabled’ company also uses Forced-tunneling the traffic will (1) get encrypted/decrypted until the SfB Edge server (2) to the other company Edge server and encrypted/decrypted again.
Now you have SfB traffic getting encrypted on an (overloaded) VPN tunnel traveling between several other systems and networks.
End user calling: “Skype for Business is a sh***. Totally useless”
Is there a solution?
Ask the CFO that you need to increase the internet bandwidth 🙂
Or… implement a Split-tunnel VPN.
SfB takes advantages of protocols like ICE and STUN/TURN to pass through routers and firewalls and get the shortest path to the other endpoint.
Let’s see the same picture now, where users don’t use a VPN or there is a complete Split-tunnel configuration:
- Home Office calls are going directly throw the Internet and encrypted only once (native done by SfB)
- The other SfB call and conferencing will go to the internal LAN throw the SfB Edge server (and encrypted only once)
- All SfB traffic will not consume VPN bandwidth
Is it important? as the Covid-19 continues to spread, more and more companies will adopt, someway or another, home office policies.
If 5% of home office of the users complaining about calls issues might not be important, but if you suddenly have 50-75% of your staff at home a SfB issue would make you look at a different perspective.
How to implements a split-tunnel for SfB?
There are many resources on the Internet to implement split-tunneling. I will not enumerate them because you need to understand how your VPN is implemented and the Windows configurations in place (local firewall, group policies, QoS)
The main concept is to ensure that all the SfB traffic can bypass the VPN. You need to:
- Ensure that the home office client can reach and route traffic to the Edge servers
- Block media ports from reaching the internal front-end servers
- And let the SfB client do the rest!
Almost there! this will get you a ‘half-split-tunnel’. Unless your VPN client is smart enough to allow the SfB client to reach any public IP address, the above solution allows them to reach the Edge servers. The traffic will bypass the VPN, and it will use the Edge servers:
To get to the complete split-tunnel solution, you actually need to configure the VPN client to route only the internal company addresses and let the remaining apps to reach the internet.
Advantages: your VPN will only have traffic for the internal applications, Skype for Business calls will go throw the fastest path.
This solution also place another challenge for companies with stricter security rules: ‘all companies PC traffic must go throw the VPN’. A good opportunity to rethink on newer security solutions 😉
And before you decide to optimize the SfB calls, here’s my IT usual recommendations:
- test first before rolling out to users: worst than some call quality issues is having no calls at all
- Ensure that you have enough resources on the help-desk to support users troubleshooting their Home LAN and the router
You can now a happy ‘home office quarantine’ 🙂
- This is not an issue/solution specific for SfB. You will face the same situation either if you are using Cisco on-premises, MS Teams, Webex, ….
- Keep safe! Careless is as bad as Panic.