Is it required for the PBR to have an ACL and route map, and then apply it to the interface?
Can it be like receiving a full routing table of public ranges from the ISP and then, create static routes with the next-hop IP as 8.8.8.8 for only zoom traffic, redistribute them into BGP, and then advertise them to the LAN segment. Here, I am changing the next-hop IP address. Can I say this is PBR?
Hello Sathish
Strictly speaking, PBR involves creating an ACL to match certain traffic, then using a Route Map to specify what action to take with that traffic. This is then applied to the interface.
Now you could theoretically do what you’re suggesting, but it’s not exactly the same thing as PBR. The main difference is that PBR allows you to make routing decisions based on policies (for example, source IP, destination IP, protocol, etc.) rather than just the destination IP address.
In the scenario you described, you are changing the next hop IP address for specific traffic (i.e. Zoom traffic), which is indeed a function of PBR. However, you are also redistributing these routes into BGP and advertising them to the LAN segment, which is more in line with traditional IP routing, not PBR.
So, while your description does implement some aspects of PBR, it’s not a full implementation of the concept. It’s more of a hybrid approach. Does that make sense?
I hope this has been helpful!
Laz
Hi Rene,
Can i use a Prefix list as a matching criteria for PBR in Cisco 8000v routers ?
Regards,
Jay
Hello Jayaraman
Your question seems simple enough, but it has quite a few implications that you should be aware of. First of all, prefix lists on any platform cannot be used in combination with route maps to perform PBR. Prefix lists are designed to perform routing protocol route filtering and are not supported in a PBR context, regardless of the platform you are using.
Now extending your question to the specific platform, let’s take a look at the operating system running on your device. The 8000v routers run IOS-XE whereas the physical 8000 series routers run IOS-XR. So the question then asks, how do IOS-XE and IOS-XR deal with routing policies?
IOS-XE uses route maps with ACLs in much the same way as shown in the lesson. IOS-XR can also use ACLs and route maps, but it also has an additional mechanism called Routing Policy Language (RPL). It is a more powerful and granular mechanism that gives you more control over routing, especially for larger and more complex networks. You can find out more info about this in the following Cisco documentation:
Remember, however, this is only for IOS XR software. IOS-XE and regular IOS use route maps and ACLs for PBR. To be absolutely sure about what your platform and IOS version combination is capable of, always check Cisco documentation!
I hope this has been helpful!
Laz