I estimated that on average, I use Google at least a dozen times on an average work day. I don’t think I will be far off to say that it is the top Internet application in almost every enterprise. While writing this article, I searched a couple of key words and arrived at a few web sites to find the specific information I was looking for. I did not have any books or references with me. More often, business users expect information on demand. It is often faster to get the information on the Internet than finding on the hard drive, and sometimes more accurate than asking your buddies.
Why this matters? Google is just an example here. For an Internet application that triggers millions of transactions almost every day in your enterprise, it is worthwhile to look “into the cloud”, and understand how your enterprise is interconnected to the rest of the world.
Google’s primary AS is 15169. It originates more than a hundred IPv4 prefixes for common apps, such as www.google.com. So how are you connected to AS15169? The average AS path length from Google is almost 3. But if you share one of the ISPs that Google peer directly with, then your path will be shorter.
The following lists the top IPv4 peers for AS 15169:ASN Name
AS3356 Level 3 Communications
AS3549 Global Crossing
AS1299 TeliaNet Global Network
AS7018 AT&T Services, Inc.
AS174 Cogent Communications
AS6762 Telecom Italia Sparkle
AS3320 Deutsche Telekom AG
AS286 KPN Internet Backbone
AS6939 Hurricane Electric, Inc.
AS3257 Tinet SpA
As an example, check the internet routing table to see how you reach IP address for Google.com. The second shorter path (through a tier one ISP) will always be preferred over the first one.
Internet_router#show ip bgp 173.194.33.104
BGP routing table entry for 173.194.33.0/24, version 2010015
Paths: (2 available, best #2, table default)
Not advertised to any peer
13789 2828 15169
…
3356 15169
…
The significance goes beyond the length of the path or how many ISPs to transit through. Larger ISPs are becoming content providers in order to further optimize performance. Just a few days ago, Level 3 signed a deal with Netflix to “support storage for the entire Netflix library of content”. Level 3 has become the primary content network for Netflix, while Akamai and Limelight remain as partners. In this case, if your users are in the entertainment business, you will be at significant advantage by peering directly with Level 3.
There are more considerations, inbound vs outbound, streaming, CDN, geographical, international, resilience and cost… more to follow.
