Hi VMinator,
To answer your question, there is no agreed upon 'standard' for portgroup names. It's all about what you are comfortable with supporting and what works for you and your organization. Kinda like server names; some companies go hardcore with naming conventions and others name them after sci-fi characters or world of warcraft bosses :smileyhappy:
The more forensics you pack into a naming standard the more control you have (i.e. for scripting, health checking, etc. see below). Also, if the very name itself answers questions on its own and saves you a phone call that's priceless. For example - unix guy says... "um what network do I choose for my new VM. My IP is blah blah blah." Well, with the right portgroup name, that question would have answered itself... and perhaps even saved some downtime in other cases by simply being clear and effective in the communication of how this virtual device is expected to function: purely expressed through a proper naming convention.
Here's another example. At my last gig we had thousands of VMs that had to move datacenters and when they landed, they needed to change IPs and start using 3 vNICs (up from 1) on each VM. Each vNIC having a different subnet mask. All support had to be carried out by an outsourced team with minimal VMware experience. The only way to support something like that and be effective is to PowerCLI. With just that naming convention alone, you can perform various tasks such as interrogate the VM and review it's portgroup settings compared to its actual IP information in the guest os, initiate a .NET ping to the VM, if there are issues take action automatically. Some actions that would be performed include, for example, changing the portgroup, or the mask on a set of guests; Or interrogate the hosts and glean network information (i.e. CDP,vSwitch, portgroup, etc. info) and compare observed network vs. expected network listed in the PG naming convention. etc. etc. The list of actions you can take are only limited by your creativity. The naming standards give you the power to be effective both in manual and automated efforts.
Again, just one man's opinion, but each site that I care and feed typically ends up with a PG standard similar to what I first described above in my previous post. Keep in mind my example naming convention is basic. There are many more attributes you can add (i.e. in vCloud deployments, in addition to the network info you may choose to identify various functionality specific to vCloud such as org-networks, etc).
TBH most companies just have portgroups named VM-Network (ok not that bad) or some random shortname that doesn't help troubleshooting. They are easy enough to fix and also modify over time if needed. You can easily drag and drop a set of VMs (although I don't personally do it this way) onto the new port group (i.e. via the networking page at CTRL+SHIFT+N) or PowerCLI it (yes! way to go). Of course, always run ping tests before and after the change. There are lots of scripts out there (or ask master lucd by posting in the VMTN PowerCLI forums). If this is net-new then you're ahead of the game and will have a standard to follow, whatever that may be.
Best of luck and have fun!