Not sure why you think FIB compression is a risk or will be a mess. It’s a pretty straightforward task.
Owen > On Sep 30, 2023, at 00:03, Mark Tinka <mark@tinka.africa> wrote: > > > >> On 9/30/23 01:36, William Herrin wrote: >> >> >> If I were designing the product, I'd size the SRAM with that in mind. >> I'd also keep two full copies of the FIB in the outer DRAM so that the >> PPEs could locklessly access the active one while the standby one gets >> updated with changes from the RIB. But I'd design the router to >> gracefully fail if the FIB exceeded what the SRAM could hold. >> >> When a TCAM fills, the shortest prefixes are ejected to the router's >> main CPU. That fails pretty hard since the shortest prefixes tend to >> be among the most commonly used. By comparison, an SRAM cache tends to >> retain the most commonly used prefixes as an inherent part of how >> caches work, regardless of prefix length. It can operate close to full >> speed until the actively used routes no longer fit in the cache. > > Well, not sure if you're aware, but starting Junos 21.2, Juniper are > implementing FIB Compression on the PTX routers running Express 4 and Junos > EVO. > > We have some of these boxes in our network (PTX10001), and I have asked > Juniper to provide a knob to allow us to turn it off, as it is currently > going to ship as a default-on feature. I'd rather not be part of the > potential mess that is going to come with the experimentation of that over > the next decade. > > Mark.
