> 2. Router: at the edge of each of our PoPs is a router. This router announces the paths packets take to CloudFlare's network from the rest of the Internet.
Umm, just curious, but I thought you used a set of redundant routers at each POP?
Or is the single router used highly redundant on its own?
Since this is all for a anycast system it might be better to have more POPs at more locations instead of trying to make a single POP bulletproof by doubling up on what could be the single largest capital expense in building a POP.
Typically a PoP could be defined as either an individual provider being brought into a facility or the location of a group of providers entering the facility (meet me room). In this instance I think they mean an individual provider (for example Level3) bringing in a feed into a data center. You would then get multiple feeds from distinct providers. Each feed would require a router for termination, and this router is typically using BGP. Since you keep multiple providers having redundant routers on each feed isn't always necessary. But there are cases where I've seen a single feed being served by redundant routers using something like VRRP. After that you would take feeds from the boarder router into our inner/core switch fabric to be distributed throughout your network. It just depends on the level of redundancy you want at each layer.
Thankyou. I remember VRRP being a bit of a mess from inception due to
the Cisco patent claims against the original IETF draft (too similar to
their patented HSRP). Are there still a lot of compatibility problems
across vendors? At home I used to use CARP (Common Address Redundancy
Protocol) on OpenBSD, but I haven't done it for awhile, and I know it's
improved a lot since then (i.e. pfsync(4), ifstated(8), ...).
Umm, just curious, but I thought you used a set of redundant routers at each POP?
Or is the single router used highly redundant on its own?