NFD36: Arista Does Micro-Segmentation
Arista had several exciting announcements at Network Field Day 36 (#NFD36).
They started by noting they had their 20th anniversary last month.
Arista’s Main Presentation Topics
Their NFD36 presentations then covered the new / expanded capabilities.
I list them below, with some brief notes:
Unified Network Management with Cloud Vision providing multi-functional NetOps.
CloudVision Demo / End-to-End Observability with CloudVision UNO (Universal Network Observability).
Multi-Domain Segmentation Services (MSS) for Zero Trust Security
Multi-Domain Ops: Visibility and Proactive Troubleshooting with CloudVision
Micro-Segmentation Services
This blog focuses on the micro-segmentation services. Which fall under the general topic of “Zero Trust”.
FWIW, I have listed already-posted blogs by other NFD36 delegates at the end of this blog. One provided an overview of the new capabilities, and the other focused more on micro-segmentation. This blog somewhat overlaps with the latter of those two.
What is micro-segmentation? It is dividing the network into small segments or groups of devices with security rule enforcement between the segments. It is policy-driven, whereas macro-segmentation often entails larger security groups and enforcement via topology, as in VLANs, VXLANs, and other network-based separation of devices and traffic.
Why micro-segmentation? It offers the opportunity for finer granularity (smaller security groupings) with a much more dynamic policy-based approach. Cisco perhaps introduced it with Security Group tagging, initially of packets on the wire, and more recently by logical Security Group tags associated with traffic flows (but not necessarily actually present in the packets). Arista’s tagging is virtual.
Whenever you do security segmentation, the next question is “how is it enforced?”
With macro-segmentation, traffic on the cabling is logically separated by VLAN or other tags. Routers and other devices that see the flows can then apply security rules. Typically the segments behave logically like separate “wires” in switches, so that devices in different segments need a router or firewall to talk to each other. Edge ports are commonly in a single VLAN and only see traffic from within that VLAN.
Micro-segmentation is more about policy enforcement for devices that are “connected to the same network or wire”. Something needs to provide enforcement. There are two common ways to provide that enforcement, shown with pros/cons in the following Arista diagram.
Note that the “Multi-Domain” aspect, and the red Cons at the left above, are Arista calling out their competition, which have separate campus and datacenter switch product lines. And yes, Cisco Catalyst and Nexus switches are managed differently (etc.)
If you pause to think about how enforcement might be done, yes, either every switch has to do enforcement, or the endpoints do. Well, a third option (e.g. Cisco IOT) is for low end VLAN-only switches at the edge to feed smarter infrastructure switches doing switch-based. That assumes everything on a small switch is in the same security segment. Which is not very flexible going forward: it is a migration technique until low end older switches can be replaced.
Host-based can distribute the workload and enforce via agent software. One concern with it is hosts (app servers, guest laptops, IOT/OT devices, etc.) where you can’t install the agent. Others include malware evading the host agent enforcement, and the potential pain of managing the agent and agent updates (“operational complexity”).
Switch-based enforcement done in switch hardware is wire speed. If not, buy better switches!
What vendors may not tell you is that hardware enforcement is likely NOT stateful. Doing wire-speed cost-effectively basically means NOT remembering prior traffic. Having said that, maybe that’s something you relegate to border firewalls, where there is (perhaps) greater risk, and lower traffic volume.
Deploying Micro-Segmentation
Arista provided a slide that nicely summarizes the process of deploying micro-segmentation.
“Micro-perimeters” doesn’t quite work for me. How about “decide what’s in each micro-segment” or “decide on your initial groupings of devices”?
Figure out what’s on your network, and check that based on actual traffic. Then decide what rules you want. Give each group of devices of interest a meaningful name. (And perhaps “Other” or “Unclassified” for leftover types of devices?)
Then do something (try for non-disruptive), and then do incremental improvement and incremental additional segmentation. Stop before it all becomes unwieldy, unmanageable.
Arista makes three good points in a subsequent slide:
The Arista presentation then walked through a demo. I’ll refer you to that rather than trying to summarize it here.
A key point is that Arista does identify flows the switch sees (assuming you have ZTX collectors), and CloudVision can suggest initial policies for previously defined device groups. You can also use CloudVision to observe traffic patterns, or pull up a stateful traffic diagram.
Once you have a policy, Arista can quickly deploy it. For switch-based, this typically means updating either a group of or all switches. Not something you’d want to do manually!
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Here’s an example policy, showing a rule for various previously defined groups:
Some Other Considerations
Micro-segmentation doesn’t require overlays and fancy protocols (VXLAN anyone?). Nor does it require topology changes!
A point I’ve previously made elsewhere: your organization needs a clear policy if you’re thinking of using micro-segmentation. Some organizations may require stateful enforcement. That means the cost of deploying firewalls or separate networks all over the place, and maintaining them.
Conclusion: used appropriately and wisely, micro-segmentation can save you from having to buy and manage a swarm of firewalls!
That’s why I think in terms of combining macro- and micro-segmentation. Use macro techniques when you need to force traffic to be routed to more central inter-segment stateful enforcement points (firewalls).
Another consideration, which some users of Cisco ACI and early Nexus switches encountered, is that micro-segmentation rules need to be stored in hardware (chips!), which likely has limited and costly “TCAM” (lookup) tables. In large datacenters with many applications, that might become an issue.
Links
Arista home page:
Arista has been active with Tech Field Day over the last 2 years. For prior presentations etc. see the first link below, the TFD Arista company page.
Tech Field Day links:
Note that new NFD36 blogs about Arista eventually may get added to the top of the list of links at the bottom of the Arista company page.
NFD36 Delegate blogs already posted:
My NFD36 Elisity blog, discussing Elisity’s micro-segmentation, which now has Arista support:
Miscellaneous
Hashtags: #PeterWelcher #CCIE1773 #NFD36 #Arista #MicroSegmentation #CloudVision
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Twitter: @pjwelcher
LinkedIn: Peter Welcher
Mastodon: @pjwelcher@techfieldday.net
I don’t know how someone can say they do microsegmentation but not isolate VMs on the same host. Does Arista integrate with OVS/NSX?