Leading edge technologies in the HEAnet network

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Leading edge technologies in the HEAnet network
Brian Nisbet John Lyons
ltnoc_at_heanet.iegt
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Overview of talk

• HEAnet FAQ - what, why, who, where.
• National and international links
• - Gigabit ethernet in the WAN
• Some services
• - Mirroring
• - Cisco Distributed Director
• Some projects
• IP routing fundamentals
• - IP routing in HEAnet using OSPF, IS-IS BGP

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What?

• HEAnet is the national network for education and
  research
• Not-for-profit, not-for-loss too.
• Operating since 1983
• Incorporated in 1997
• Located in Dublin
• PoPs in Cork, Dublin, Citywest, Galway, Limerick
  Kilcarbery

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Why?

• Intercommunication
• Resource sharing
• Economies of scale
• Research collaboration
• Network technology
• National strategy

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Who?

• 40 institutions (universities, ITs, )
• Owned by the members
• Small central staff
• Collaboration with members
• International associations/partnerships

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Where?

• HEAnet Ltd., Ground Floor, Brooklawn House,
  Crampton Ave, Shelbourne Rd, Dublin 4
• Tel [phone] Fax [phone]
• E-mail info_at_heanet.ie or webmaster_at_heanet.ie
  
• GPS Coordinates 53.3381ºN 6.2403ºW
• Web http//www.heanet.ie

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Network Map
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DCU Bandwidth Usage

• DCU MRTG (12th 20th March)

Maximum bandwidth available to DCU 63 Mbps
ATM over STM1
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Mantova Pic
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Gigabit Backbone

• Citywest Galway (March 12th)

Citywest NOC March 17th 25th
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Gigabit Ethernet WAN

• Bigger, Better, Faster?
• Pros
• Mass Produced
• Less Demanding of Hardware
• Less Complex to Configure
• Higher Bandwidth
• Cheaper

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Gigabit Ethernet WAN

• Cons
• Slower convergence times
• More difficult to troubleshoot
• Next steps may lose some of the advantages
• 10GE (add another zero)
• Complicates things by adding more framing for
  long haul.
• May cost the same as STM-64.

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Gigabit Ethernet WAN

• National Backbone Links
• Router to router, very straightforward.
• Client Links
• HEAnet to TCD, Ratelimited 120Mbps over GE.
• Cisco 7200 onsite in TCD. Point-to-point from
  there into a Routing-Switch.
• Allows better visibility of circuit and
  development of Routing-Switches makes things
  cheaper.

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International Links

• 155Mbps Teleglobe, Abilene StarTap
• 622Mbps GlobalCrossing
• 1Gbps JANET, Canet4, INEX
• 2.5Gpbs Géant

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Some Operational Services

• National Information Server
• IP address and Domain registration
• Listserv
• Statistics
• Seminars, training
• Databases
• Webhosting
• Mirroring
• IPv6
• NTP
• Network security evaluation
• Hot standby (Cisco DD)

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Mirroring - ftp.heanet.ie

• 2.2 Terabyte Server with dual GigE connectivity
• IPv6 Capable in HTTP/FTP and RSYNC
• One of the busiest mirrors in Europe and an
  official mirror of RedHat, Debian, FreeBSD
• Over 60 projects mirrored
• Developed custom Apache patches to tweak service.
• mirrors_at_heanet.ie

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Hotstandby Web services

• HEAnet offer failover protection for webservers
  using Cisco Distributed Director technology
• Router (Cisco 3620/7200) acts as an authoritative
  DNS server with a TTL of 0
• Clients cannot cache the DNS records
• Router monitors the primary webserver with full
  TCP connections on port 80 at specified intervals
  (eg. Every 10 seconds)

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Cisco Distributed Director

• Router has IP address of both main webserver and
  backup standby server
• If the router cannot connect to the main
  webserver it will redirect queries to standby
• Continues to initiate connections to main
  webserver and reverts back to it when the
  webserver recovers
• In HEAnet CDD is simply set-up to telnet to
  webserver on port 80. If it receives a response
  it considers the webserver to be up but more
  granularity can be added.
• Has limitations
• - IPv6 not supported
• - https not supported

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Some HEAnet service developments

• IPv6 (Also a service)
• Test traffic project
• Multicast
• MAN
• Honeypots
• Videoservices
• Netflow
• PKI
• National Backbone
• Next Generation Internet

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IP routing Fundamentals

• Routing is the process of selecting the
  interfaces through which a packet should be sent
• Forwarding is the process of actually moving this
  packet once the route has been determined
• Classful routing only passes network addresses,
  classless routing uses both network and subnet
  addresses
• Classless interdomain routing (CIDR) was brought
  in in a bid to reserve IPv4 addresses and allows
  blocks of class C addresses to be
  combined/aggregated eg. 192.168.1.0 /21

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More fundamentals

• Variable length subnet masks (VLSM) - greater
  granularity eg.192.168.0.0/28
• Distance Vector protocols use hop count as a
  metric, link state (eg. OSPF) use cost. Hybrid
  protocols like EIGRP can use complex rules
  involving delay, reliability
• Convergence is the length of time after a network
  change (Interface/line down, router added
  etc.)that routing tables take to update
• An Autonomous system (AS) is a group of IP
  networks operated by one or more network
  operator/s which has a single and clearly defined
  external routing policy

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Rip v1/v2

• RIPv1 RFC1058
• - Classful, Periodic updates, transfers entire
  routing tables, distance vector, uses holddown
  timers.
• RIPv2
• - Added classless, authentication, multicast
  support.
• Uses routing by rumour as it only sees directly
  connected routers
• Both of these routing protocols are inefficient
  and
• are now only used on very small networks. They
  have been phased out in favour of more
  intelligent
• Interior gateway protocols (IGPs) such as OSPF
  and IS-IS.

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OSPF Overview

• Features
• - Supports CIDR/VLSM
• - Fast convergence
• - Uses multicast addresses for hello packets
• - Load balancing
• - Uses areas to cut down CPU usage
• Uses hello packets to establish adjacencies
  initially via
• a 6 step process
• Once adjacency established it uses regular Link
  State advertisements (LSA) and Link state updates
  (LSU) to describe links adjacencies changes

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OSPF

• 9 types of LSA, 5 of which are used extensively
• 1-Router link
• 2-Network link
• 3-Network summary
• 4-ASBR summary
• 5-AS external.
• (other 4 for TOS)
• Link state databases (LSDB) built from info in
  LSAs
• Each router in an Area has the same LSDB and
  using this the SPF algorithm (Dijkstra) to
  build its routing table
• Its an efficient quiet routing protocol as it
  can have separate LSDB for each area only sends
  LSA updates

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OSPF

• Works under different network topologies
  differently
• - Broadcast multiaccess (LAN)
• - Point to Point (eg. Serial connection)
• - Point to Multipoint (eg ATM using multiple
  VCs)
• - Point to Multipoint (Non broadcast multi
  access (NBMA))
• Reacts quickly to network changes (Line down,
  router death)
• - Hello interval every 10 secs
• - Dead interval (Link down) is 4 times hello
  interval
• Routing descisions based on cost of 100000000/1
• - Cost ranges from 0 to 65535 with 0 being the
  best
• - 100Mb OSPF cost of 1
• - OSPF can do load balancing between same cost
  routes

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OSPF in HEAnet

• In HEAnet we have only one area (backbone area
  0)although we are investigating the use of
  multiple areas in the future (or using IS-IS)
• In conjunction with static routes and BGP we use
  OSPF to route traffic throughout our internal
  network
• Routers in DCU have full visibility of all
  routers running OSPF
• in our AS ie. They have the same LSDB as the
  other routers in the AS
• Does have its limitations
• - Currently running OSPF v2 which doesnt
  handle IPv6
• - OSPF v3 does but isnt considered stable enough
  yet
• - For IPv6 we need to run another routing
  protocol IS-IS

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IS-IS

• IS-IS (Intermediate System to Intermediate
  System). Part of the OSI standard.
• ISO/IEC 10589, RFC 1195 and RFC 2763
• Not originally designed for IP.
• Uses Link-State PDUs, similar to OSPF LSAs.
• Extensible Protocol, updated to deal with IPv6
  faster than OSPF.
• Add more Type-Length-Values to the PDUs to handle
  more protocols.

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IS-IS in HEAnet

• Used purely for IPv6 routing within the HEAnet
  network.
• Communication between routers.
• IPv6 connections to clients.

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BGP

• BGP (Border Gateway Protocol) is an EGP (External
  Gateway Protocol) and an IGP (Internal Gateway
  Protocol).
• RFC 1771
• Deals with AS (Autonomous Systems)
• Exchanges routing information between peers.
• Makes routing decisions based on a number of
  different criteria applied to each route.

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BGP

• These criteria feed into the BGP Best Path
  Algorithm. Each step is gone through until a
  definite routing decision can be made.
• Invalid paths are ignored.
• Common values/criteria
• Local Preference
• AS Path Length
• Multi Exit Discriminator (MED)
• Will eventually choose the path to the router
  with the lowest IP address.

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BGP in HEAnet

• We have BGP peerings with all of the networks we
  directly connect to eg Géant, JANET, Canet4,
  Global Crossing, Teleglobe etc.
• A large number of the routers in HEAnet form part
  of our internal BGP mesh.
• Allows for proper route selection to any
  accessible point in the internet from anywhere in
  HEAnet.

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Contacts

• http//www.heanet.ie
• info_at_heanet.ie

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Questions ?