Predictive Anycast traffic shaping
Gateway devices at different sites of a primary Anycast network provide access to the sites by advertising a first set of Anycast addresses. A secondary shadow Anycast network advertises different second sets of Anycast addresses from the different sites in order to predetermine traffic shifts that occur as a result of changing one or more of the second set of Anycast addresses that are advertised from one or more of the sites. A traffic shifting device may implement a predetermined traffic shift in the primary Anycast network by selecting a particular second set of network addresses that produces a traffic shift at least equal to the predetermined traffic shift, mapping the particular second set of network addresses to a modified first set of addresses, and modifying routing in the primary Anycast network by advertising the modified first set of addresses instead of the first set of addresses.
1. A method comprising:
advertising a first set of addresses with one or more variations and a second set of addresses without the one or more variations from at least a first site;
determining different load fluctuations at the first site after advertising each of the first set of addresses with the one or more variations from at least the first site;
detecting an excess load at the first site resulting from requests that are directed to the second set of addresses; and
modifying said advertising of the second set of addresses from the first site by advertising one or more addresses of the second set of addresses with a variation that is derived from a particular variation of the first set of addresses, wherein the particular variation of the first set of addresses produced a particular load fluctuation in proportion to the excess load.
2. The method of claim 1 , further comprising:
advertising, from a second site, the first set of addresses, wherein the first set of addresses are in a first address space that is not exposed to devices that submit the requests and the second set of addresses are in a second address space that is exposed to the devices,
and wherein the first set of addresses comprises a different network subnet, address block, address prefix, or range of Internet Protocol (“IP”) addresses than the second set of addresses.
3. The method of claim 1 , wherein determining the different load fluctuations comprises:
performing a catchment measurement at the first site after advertising each variation of the of the first set of addresses;
mapping each variation in the first set of addresses and a load fluctuation detected in the catchment measurement resulting from that variation to a corresponding variation in the second set of addresses.
4. The method of claim 1 , wherein determining the different load fluctuations comprises:
monitoring the load fluctuations that result at the first site from advertising each variation of the first set of addresses from at least the first site while continuing to advertise the second set of addresses unchanged.
5. The method of claim 4 , wherein modifying said advertising of the second set of addresses comprises:
determining that the particular load fluctuation created as a result of the particular variation to the first set of addresses is sufficient to resolve the excess load at the first site;
mapping changes to the first set of addresses that produced the particular variation to changes in the one or more addresses of the second set of addresses; and
changing the one or more addresses in the second set of addresses that are advertised from the first site.
6. The method of claim 1 , wherein modifying said advertising of the second set of addresses comprises:
providing test traffic to measure the load fluctuations at the first site that result from advertising each variation of the first set of addresses, while continuing to advertise the second set of addresses; and
mapping the particular variation of the first set of addresses to changes in the one or more addresses of the second set of addresses in response to the particular load fluctuation being sufficient to resolve the excess load.
7. The method of claim 1 further comprising:
receiving a first set of requests, that are directed to the one or more addresses, at the first site before said modifying; and
shifting a second set of requests, that are directed to the one or more addresses, away from the first site to a second site after said modifying.
8. The method of claim 7 , wherein modifying said advertising of the second set of addresses comprises:
indicating that the one or more addresses are not accessible at the first site and are accessible at the second site by withdrawing advertisements of the one or more addresses from the first site and continuing to advertise the one or more addresses from the second site.
9. The method of claim 7 , wherein the second set of requests generate the excess load at the first site.
10. The method of claim 1 , wherein modifying said advertising of the second set of addresses comprises:
advertising the second set of addresses from the first site with the one or more addresses removed or modified from said advertising.
11. The method of claim 1 further comprising:
advertising the second set of addresses from a second site; and
wherein modifying said advertising of the second set of addresses comprises:
removing the one or more addresses from the second set of addresses being advertised from the first site;
continuing said advertising of the second set of addresses with the one or more addresses from the second site.
12. The method of claim 1 further comprising:
advertising the second set of addresses from a second site; and
wherein modifying said advertising of the second set of addresses comprises:
modifying said advertising of the second set of addresses from the first site by increasing a network path length associated with accessing the one or more addresses from the first site;
continuing said advertising of the second set of addresses from the second site with a network path length associated with accessing the one or more addresses from the second site being less than the network path length associated with accessing the one or more addresses from the first site.
13. The method of claim 1 further comprising:
receiving a first plurality of requests that create the excess load at the first site before advertising the one or more addresses with the variation;
receiving a second plurality of requests that create an acceptable load at the first site after advertising the one or more addresses with the variation; and
receiving a third plurality of requests that shift the excess load from the first site to a second site after advertising the one or more addresses with the variation.
14. The method of claim 1 further comprising:
shifting the excess load from the first site to a second site as a result of requests that are directed to the one or more addresses routing to the second site, instead of the first site, after advertising the one or more addresses with the variation.
15. The method of claim 1 further comprising:
deterministically shifting traffic equaling the excess load from the first site to a second site in response to advertising the one or more addresses with the variation.
16. A system comprising:
one or more processors configured to:
advertise a first set of addresses with one or more variations and a second set of addresses without the one or more variations from at least a first site;
determine different load fluctuations at the first site after advertising each of the first set of addresses with the one or more variations from at least the first site;
detect an excess load at the first site resulting from requests that are directed to the second set of addresses; and
modify said advertising of the second set of addresses from the first site by advertising one or more addresses of the second set of addresses with a variation that is derived from a particular variation of the first set of addresses, wherein the particular variation of the first set of addresses produced a particular load fluctuation in proportion to the excess load.
17. The system of claim 16 , wherein modifying said advertising of the second set of addresses comprises:
advertising the second set of addresses from the first site with the one or more addresses removed or modified from said advertising.
18. The system of claim 16 , wherein the one or more processors are further configured to:
advertise the second set of addresses from a second site; and
wherein modifying said advertising of the second set of addresses comprises:
removing the one or more addresses from the second set of addresses being advertised from the first site;
continuing said advertising of the second set of addresses with the one or more addresses from the second site.
19. The system of claim 16 , wherein the one or more processors are further configured to:
advertise the second set of addresses from a second site; and
wherein modifying said advertising of the second set of addresses comprises:
modifying said advertising of the second set of addresses from the first site by increasing a network path length associated with accessing the one or more addresses from the first site;
continuing said advertising of the second set of addresses from the second site with a network path length associated with accessing the one or more addresses from the second site being less than the network path length associated with accessing the one or more addresses from the first site.
20. A non-transitory computer-readable medium, storing a set of processor-executable instructions, which, when executed by one or more processors, cause the one or more processors to:
advertise a first set of addresses with one or more variations and a second set of addresses without the one or more variations from at least a first site;
determine different load fluctuations at the first site after advertising each of the first set of addresses with the one or more variations from at least the first site;
detect an excess load at the first site resulting from requests that are directed to the second set of addresses; and
modify said advertising of the second set of addresses from the first site by advertising one or more addresses of the second set of addresses with a variation that is derived from a particular variation of the first set of addresses, wherein the particular variation of the first set of addresses produced a particular load fluctuation in proportion to the excess load.