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Agenda

Técnicas de Alta Disponibilidade para NAPs Marcelo Molinari – Foundry Networks do Brasil marcelo@foundrynet.com. Agenda. LINX topology overview AMS-IX topology overview Metro Ring Protocol Virtual Switching Redundancy Protocol. London Internet Exchange (LINX). LINX Topology. LINX Topology.

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Agenda

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  1. Técnicas de Alta Disponibilidade para NAPsMarcelo Molinari – Foundry Networks do Brasilmarcelo@foundrynet.com

  2. Agenda • LINX topology overview • AMS-IX topology overview • Metro Ring Protocol • Virtual Switching Redundancy Protocol

  3. London Internet Exchange (LINX)

  4. LINX Topology

  5. LINX Topology • The LINX Network consists of two separate high-performance Ethernet switching platforms installed across seven locations. • Switches from two equipment vendorsare deployed in two separate networks to provide an extra level of fault-tolerance, the logic being that both systems shouldn't develop the same fault at the same time.

  6. LINX Topology • Two switches are installed in every LINX location, and the locations are interconnected by multiple 10 gigabit Ethernet circuits to form two physically separate backbone rings. • Most LINX members connect to both switching platforms, which reduces the impact of any downtime on a single network element. • Management of the logical redundancy of the network is done using MRP (Metro Ring Protocol). In the event of the loss of a network segment, MRP activatesa redundant link within tenths of a second and restore connectivity.

  7. LINX Aggregated Traffic Statistics

  8. Amsterdam Exchange (AMS-IX)

  9. AMS-IX Topology

  10. AMS-IX Topology • AMS-IX is a distributed exchange, currently present at five independent co-location facilities in Amsterdam. • The AMS-IX topology is built around two hub/spoke arrangements. • The core switches are Foundry Networks NetIron MLX-32 switches. • Members connected with GigE, 100Base-TX or 10Base-T ports are connected to Foundry NetworksBigIron 15000 and BigIron RX-8 switches. • Members with a 10GbE port are connected to Glimmerglass Networks photonic cross-connects. These L1 switches connect the member 10GbE ports to BigIron RX-16 or NetIron MLX-16 switches.

  11. AMS-IX Topology • The two core switches run VSRP (Virtual Switch Redundancy Protocol) to define the active hub/spoke and to automatically fail over to the other, based on pre-defined triggers (e.g. link failure). • All edge switches from Foundry follow VSRP automatically. The Glimmerglass switches follow the VSRP failover based on software developed at AMS-IX. • Members can connect to the AMS-IX infrastructure at any of the five AMS-IX co-locations, at 100 Mbit/s, 1 Gbit/s or 10 Gbit/s.

  12. AMS-IX Traffic Statistics

  13. Metro Ring Protocol

  14. Metro Ring Protocol (MRP) • Metro Ring Protocol is a Layer 2 protocol designed to provide SONET-like, high speed, fault tolerant, fast recovery for Metro Ethernet networks. • MRP SONET-like features provide: • Sub-second failover • Efficient use of bandwidth with topology groups (802.1s based) • Scalable protection for multiple VLANs • Large Scale L2 MANs with multi-ring support • Highly flexible network designs • Works with other L2 features • Runs on all Ethernet and PoS/SDH interfaces, including 10 Gigabit

  15. How it works • A single node is defined as the Ring Master Node • All other nodes are defined as Ring Member Nodes • The Master Node prevents loops by blocking its secondary port • Ring Hello Packets are generated by the Master Node to check ring integrity • As long as the master sees its own Hello packets on the secondary port, ring health is verified, and secondary port remains blocked RHP RHP RHP RHP Primary (Forwarding) Secondary (Blocking)

  16. NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 Rapid Failover FAULT • Hello packets are hardware forwarded by the nodes in the ring to ensure fastest failure detection. • Master considers ring broken if no Hello packets are received within 300 ms (3 consecutive Hellos are lost). • If no Hellos are received, Master transitions secondary port into forwarding state to restore ring connectivity. • To provide reliable flushing of stale MAC entries, Master sends 3 consecutive TCN notifications. • By changing timers and using messages sent by the node where the ring broke, it is possible to achieve recovery times from 150 ms to 200 ms. RHP RHP RHP RHP TC TC TC

  17. NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 Link RestorationPreventing Temporary Loops Link restored • When an MRP port goes up, it goes into pre-forwarding mode to avoid the creation of temporary loops. • In pre-forwarding mode the port forwards no data, but only the ring hello packets from the master. • Master sees its own RHP, detects that ring integrity has been restored, puts its secondary port in blocking mode. • From that point onwards, master sends RHPs with the Forwarding flag bit set, indicating that members should transition their ports from pre-forwarding to forwarding. • The Forwarding flag bit is always set, as long as the master is blocking its secondary port. RHP PF RHP PF RHP RHP RHP RHP F F RHP RHP

  18. Topology Groups Topology Group A VLAN running a control protocol (or more) that controls the active topology for the whole topology group. Control protocols: STP, RSTP, MRP, VSRP. Master VLAN A VLAN running NO control protocol of its own but rather follows the active topology of the master VLAN.. Member VLAN Member VLAN Group A group of VLANs running NO control protocol of their own but rather follow the active topology of the master VLAN. VLAN groups are defined via the “vlan-group” command.

  19. Efficient use of Ring Bandwidth • MRP Supports Multiple Topology groups within a Ring • An MRP Node can be both a Master node and Member Node for different topology groups • Each Topology group contains a Master VLAN and Member VLANs • Master VLANs generate Hello packets and block secondary ports • 4094 VLANs can be divided among up to 255 Topology groups Topo Group 1 Topo Group 2

  20. Using Multiple Rings • There are 3 ring scenarios: • Single ring • Rings that don’t overlap • Overlapping rings that share links • Each Ring runs its own instance of MRP • A ring node can be Master for Multiple rings Single Ring Non-Overlapping Ring Overlapping Rings Phase II Phase I

  21. BigIron 8000 BigIron 8000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 Example Scenarios – Phase I • High-speed 10 GE trunks for Metro rings or IXPs • Provides sub-second fault-detection and fail-over • Superior scalability: no limit on maximum number of nodes per ring • Counter rotating topology groups provide efficient use of bandwidth S6 Secondary port Ring 2 S1 Master node Primary port S5 Ring 1 S2 S5 S4 Ring 3 S4 S3 Ring 4 Master node

  22. BigIron 8000 BigIron 8000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 Example Scenarios – Phase II • Shared ring support • Increased reliability • Increased bandwidth S6 Secondary port Ring 2 Master node S1 Primary port Master node S5 Ring 1 S2 S5 S4 Ring 3 S4 S3 Ring 4 Master node

  23. S1 BigIron 8000 BigIron 8000 BigIron 8000 BigIron 8000 S2 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 BigIron 4000 S3 Interface Flexibility • Support for Mixed interfaces • 10Gig & Gig • Gig & 10/100 • 10Gig & PoS/SDH • Support for Trunked interfaces • 10Gig & Gig • PoS/SDH Slower link S6 S6 Secondary port Secondary port Master node Master node S1 Primary port Primary port S5 S5 S2 S4 S4 S3

  24. MRP – Summary of Benefits • Fast, sub-second, predictable fail-over functionality • Maximizes ring bandwidth utilization • Cost effective scalable solution for MAN resiliency • Attractive alternative to STP • Utilizes 802.3 Ethernet Packet standards and MACs • Can be combined with other Foundry features to provide complete end to end MAN designs

  25. Virtual Switch Redundancy Protocol

  26. Virtual Switch Redundancy Protocol • VSRP provides an alternative to Rapid Spanning Tree Protocol (RSTP) in dual homed/mesh configurations, providing sub-second fail-over and recovery. • VSRP features provide: • Sub-second fail-over • Efficient use of mesh bandwidth – no blocked links • Block and unblock ports at the per-VLAN group level • Large scale L2 MANs with multi-tiered support • Highly flexible network designs • Configurable tracking options • Works with other L2 features • Works with all Ethernet interfaces, including 10 Gigabit • VSRP is based on VRRP-E & can provide L2 and L3 backup

  27. BigIron 8000 BigIron 8000 S3 S4 BigIron 4000 BigIron 4000 BigIron 4000 S5 How it works • VSRP uses an election process to select a Master switch and up to 4 backup switches for each VLAN: higher configured priority wins; if equal, higher IP address wins. • Only the Master switch forwards data, while Backup switches block traffic on all VSRP configured interfaces within the VLAN (or the topology group). • Master switch sends Hello packets to all backup switches • Switches do not have to be VSRP aware. VSRP aware provides faster failover. • VSRP can track ports and decrease the priority of VSRP active switch in case a tracked port goes down. VSRP Master VSRP Backup S1 S2 F B B B F F Hello Hello VSRP Aware

  28. NetIron 800 NetIron 800 NetIron 800 NetIron 800 NetIron 800 NetIron 800 NetIron 400 NetIron 400 Rapid Failover Master Backup Backup • A VSRP Backup switch monitors Hellos from the Master. • If no Hellos are received for Master Dead Interval (default 300 ms), Backup goes into Hold Down state, starts sending periodic Hellos. • Hold Down interval is by default 300 ms, and it allows for the election of a new master. • If the switch is elected as Master, it sets its port into forwarding state, sends 3 TCNs. • A VSRP aware switch receives TCN, and looks for the new master. Hellos of the new master will be received on a different port. • A VSRP aware switch shifts the MAC addresses learned on the failed port to the new port. B B FAULT F Hello Hello Hello Master Backup F B Dn FAULT Hello Hello Mac Type:D = Dynamic, S = Static, H = Host, R = Router MAC Port Age Type 0060.f320.23a8 2 0 D 0030.1b07.0694 2 0 D 00d0.b758.88dc 2 0 D 0004.8039.5f00 2 0 D

  29. NetIron 800 NetIron 800 NetIron 800 NetIron 800 NetIron 800 NetIron 800 NetIron 400 NetIron 400 Link RestorationSwitching Back to Original Master Link restored (Orig. Master) Backup Master Backup • When the failed link is restored, the original Master remains as a Backup. • Original Master receives inferior Hello from the current Master, so it immediately replies with its own Hello, switches into Hold Down state (300 ms), starts sending periodic Hellos • Current Master receives superior Hello, so it switches into Backup mode. • If no superior Hellos are received during Hold Down interval, original Master considers itself the new current Master, and sets its port in Forwarding mode. • New Master sends out 3 TCNs. • A VSRP aware switch receives TCN, and looks for the new master. Hellos of the new master will be received on a different port. F B B Hello Hello Hello Hello Hello Hello Backup Master Backup B B F Hello Hello Hello • A VSRP aware switch shifts the MAC addresses to the new port. Mac Type:D = Dynamic, S = Static, H = Host, R = Router MAC Port Age Type 0060.f320.23a8 1 0 D 0030.1b07.0694 1 0 D 00d0.b758.88dc 1 0 D 0004.8039.5f00 1 0 D

  30. BigIron 8000 BigIron 8000 S4 S3 BigIron 4000 BigIron 4000 BigIron 4000 S5 Efficient use of Uplink Bandwidth • VSRP supports topology groups to fully utilize switches and links • Topology groups are a collection of VLANs • Each yopology group contains a Master VLAN and Member VLANs • VSRP configured switches can be Master for some topology groups while backup other for others • 4094 VLANs can be divided among up to 255 Topology groups Master topology group 1 Backup topology group 2 Master topology group 2 Backup topology group 1 Hello Packets S1 S2 VSRP Aware Topology group 1 = Master VLAN 1 Member VLANs 2 to 2048 Topology group 2 = Master VLAN 2049 Member VLANs 2050 to 4096

  31. NetIron 800 NetIron 800 NetIron 800 NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 NetIron 400 VSRP Domains • VSRP can be configured in separate domains within the same VLAN to allow for larger topologies. • Topology groups can be designed to use unique paths in each domain. • A TTL value within the VSRP Hello packet controls how deep the packet goes into the network. • TTL is being decremented by 1 at each VSRP aware switch. • Default TTL is 2, which allows Hello to traverse one VSRP aware switch to go to another VSRP active switch. VSRP Active VSRP Domain 1 (VRID 1) VSRP Aware VSRP Active VSRP Domain 2 (VRID 2) VSRP Aware VSRP Active VSRP Domain 3 (VRID 3) VSRP Aware

  32. NetIron 800 NetIron 800 NetIron 800 NetIron 800 NetIron 400 NetIron 400 Intelligent Port Level Control • VSRP can be configured to run only on designated ports • Only VSRP configured ports are placed in blocking for Backup switches • Supports host attachments and dual port NICs: host facing ports are configured as VSRP free. • Works in combination with MRP to provide flexible Metro / Enterprise Ethernet designs. MRP Master Backup VSRP Aware Dual Homed Servers

  33. BigIron 8000 BigIron 8000 S3 S4 BigIron 4000 BigIron 4000 BigIron 4000 S5 VSRP-Aware Switches • Both VSRP-Aware and Non VSRP-Aware switches can be used as edge devices • VSRP-Aware switches recognize the VSRP Hello packet sent by the Master, and then create an table which contains the VRID of the VLAN which sent the VSRP Hello plus the incoming port where the VSRP Hello was received. • When the VSRP-Aware switch sees a Hello packet coming from a different port, it quickly moves the MAC address table entries to the new port. VSRP Master VSRP Backup S1 S2 F B B B F F Hello Hello VSRP Aware VSRP Aware VSRP Aware

  34. BigIron 8000 BigIron 8000 S3 S4 BigIron 4000 BigIron 4000 BigIron 4000 S5 Non VSRP-Aware Switches • Non VSRP-Aware switches can be used as edge devices, but they do not recognize VSRP Hello packets. • MAC entries will age out or they will eventually be learned from the new port. • This results in slow convergence when the Master fails. • Solution is to configure “VSRP Fast Start” in the VSRP Master and Backup nodes. • VSRP Fast Start disables and re-enable the ports before transitioning from Master to Backup. This causes a MAC address flush in the edge devices which makes convergence faster. VSRP Master VSRP Backup S1 S2 F B B B F F Non VSRP Aware Non VSRP Aware Non VSRP Aware

  35. VSRP – Summary of Benefits • Fast, sub-second protection without Spanning Tree • Combines both switching and routing redundancy • Provides default gateway redundancy if needed • Supports topology groups for full link utilization • Can be combined with other Foundry features to provide complete end to end MAN designs

  36. References • LINX - https://www.linx.net/ • AMS-IX - http://www.ams-ix.net/ • “I can feel your traffic” - http://www.jasinska.de/ • MRP- http://www.foundrynet.com/pdf/wp-mrp.pdf • VSRP - http://www.foundrynet.com/pdf/wp-vsrp.pdf

  37. Thank You !Marcelo Molinari – Foundry Networks do Brasilmarcelo@foundrynet.com

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