Time to rewind from the new and shiny and get back to roots of networking. BGP is one of those odd protocols that is foundational to the functioning of the internet but yet somewhat hard to get experience with.  Say what you will about this venerable protocol, it’s been here a while and it is not going anywhere any time soon. I’ve been doing BGP since around late 1999, and I completely fell into it by accident, having only the Cisco Internet Routing Architectures book (which I literally read cover to cover) and the Ulysses Black Routing Protocols Book  and whatever I could find on a random search engine to guide me, and that was only after having to learn on the CLI for the first 6-7 months. In actuality, that is how many of the folks of my vintage came into doing BGP. Someone needed to announce some routes that were allocated to them by an RIR, or bring up some multi-homing or whatever.

With multipath, the distribution of  routes would be almost even (50-50) to both ISP1 and ISP2. However when you want to override this default behavior, you tag the incoming prefixes with BANDWIDTH community to distribute unequal prefixes to ISP1 and ISP2.

Based on these bandwidth attribute, router internally calculates on how the distribution of these prefixes to ISP1 and ISP2.

multipath = Equal distribution to ISP1 and ISP2

multipath+bandwidth  = Unequal distribution based on the bandwidth tag

BGP Looking Glass servers are computers on the Internet running one of a variety of publicly available Looking Glass software implementations. A Looking Glass server (or LG server) is accessed remotely for the purpose of viewing routing info. Essentially, the server acts as a limited, read-only portal to routers of whatever organization is running the Looking Glass server. Typically, publicly accessible looking glass servers are run by ISPs or NOCs.

Click 'Read more' to see the list of BGP Looking glass servers accessible via telnet.  

Category 2 - IPv4 and IPv6 BGP Route Servers by region (TELNET access)