1 Merit Network: Connecting People and Organizations Since 1966 Business Continuity A Networking Perspective Bob Stovall Merit Annual Meeting June 22 & 23, 2006

2 Merit Network: Connecting People and Organizations Since 1966 Network Continuity Physical Diversity Network Diversity Routing Diversity Environmental Diversity

3 Merit Network: Connecting People and Organizations Since 1966 Physical Diversity Redundancy l Entrance/Path diversity l Building Diversity l Diverse provider connections

4 Merit Network: Connecting People and Organizations Since 1966 What are Tier 1,2,3 Providers? l Many opinions about this! l Tier 1’s run a national backbone network l Connect to the rest of the Internet only via no- cost interconnections (peering) l Peer at most exchange points l Examples: AT&T, UUNET, Global Crossing, Qwest, Savvis, Sprint, Cogent, Level 3

5 Merit Network: Connecting People and Organizations Since 1966 Tier 1 Connectivity Example AS 3 AS 1 AS 4 AS 2 Customer A Customer D Customer C Customer B 4 Tier 1’s = AS Each peers with all others Each only announces its own customers

6 Merit Network: Connecting People and Organizations Since 1966 Tier 1 Example (cont’d.) If connection between AS 4 & AS 1 breaks Customer B can’t get Customer A’s routes AS 3 AS 1 AS 4 AS 2 Customer A Customer D Customer C Customer B

7 Merit Network: Connecting People and Organizations Since 1966 What are tier 2’s and 3’s l Tier 2: Regional network l Purchases transit from other Internet Service Providers and no-cost interconnections (peers) with others. l Examples: Merit, WiscNet, OARNet, etc. l Tier 3: Smaller geographic region l Purchases transit from other Internet Service Providers. l Examples: M-33 Access, SpeedNet, Modem Pool, etc.

8 Merit Network: Connecting People and Organizations Since 1966 Tier 2 Example AS 5 = Tier 2 If AS 5 were only connected to AS 1, its routes wouldn’t be announced Needs to buy transit from two Tier 1’s AS 3 AS 1 AS 4 AS 2 Customer D Customer C Customer B AS 5 Customer E

9 Merit Network: Connecting People and Organizations Since 1966 Tier 2 Example AS 5 now stays connected AS 3 AS 1 AS 4 AS 2 Customer A Customer D Customer C Customer B AS 5 Customer E

10 Merit Network: Connecting People and Organizations Since 1966 Routing Diversity Redundancy l Requires physical diversity l One provider or two. l How many connections to each provider? Two Aspects l Your local site to your provider(s) l Your provider(s)’ connection to the Internet

11 Merit Network: Connecting People and Organizations Since 1966 Customer-Provider Option 1 Customer Provider A One connection to one provider Pro: none Con: 3 possible points of failure

12 Merit Network: Connecting People and Organizations Since 1966 Customer-Provider Option 2 Two connections to one provider Pro:Circuit redundancy Con: Single point of failure in network hardware & facilities Customer Provider A

13 Merit Network: Connecting People and Organizations Since 1966 Customer-Provider Option 3 Two connections to single provider at different provider attachment points Pro: Circuit and provider facility redundancy Con: Single point of failure at customer end Customer Provider A Tier 1/2/3

14 Merit Network: Connecting People and Organizations Since 1966 Customer-Provider Option 4 Two connections to single provider at different customer and provider attachment points Pro: No single point of failure. Provider should be a Tier 1 or connected to multiple commodity providers. Customer Provider A Tier 1/2/3 Customer

15 Merit Network: Connecting People and Organizations Since 1966 Customer-Provider Option 5 One connection to two providers at different customer attachment points Pro: No single point of failure. Con: Could create ongoing routing and load balancing issues. Customer Provider B Provider A Tier 1/2/3 Customer Tier 1/2/3

16 Merit Network: Connecting People and Organizations Since 1966 Environmental Power l UPS and power generator l Diverse circuits and power panels l Diverse feeds from power company Heating and Cooling l Ensure cooling capacity for data node l Backup air conditioning/cooling

17 Merit Network: Connecting People and Organizations Since 1966 Thank You