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Design of a Diversified Router: Model and System Overview

Design of a Diversified Router: Model and System Overview. Jon Turner, John DeHart, Fred Kuhns jon.turner@wustl.edu , jdd@arl.wustl.edu , fredk@arl.wustl.edu http://www.arl.wustl.edu/arl. Outline. What is NOT covered in these slides JST’s original slides Schedule Model Traffic Types

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Design of a Diversified Router: Model and System Overview

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  1. Design of aDiversified Router:Model and System Overview Jon Turner, John DeHart, Fred Kuhnsjon.turner@wustl.edu, jdd@arl.wustl.edu, fredk@arl.wustl.edu http://www.arl.wustl.edu/arl

  2. Outline • What is NOT covered in these slides • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • Switch • MetaLink Loopback Block • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  3. Not Covered • Control • Installation • Configuration • Initialization • Monitoring • … • End Host • Substrate/Meta Model • Details about how PlanetLab works. • These are very important topics but for now we will talk about the Data Path in the Network.

  4. Outline • What is NOT covered in these slides • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • Switch • MetaLink Loopback Block • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  5. up to 10 1GEinterfaces PE/GP PE/NP Line Card . . . . . . 10 GE Switch Switch Blade System Architecture compute blade with disk Radisys7010 Radisys 7010 with RTM 1 GE for control 10 Gb/s for data • General purpose blades. • shared blades run Plab OS • no change to current apps • also support dedicated blades • use separate blade server to preserve ATCA slots for NPs • NP blades. • support dedicated PEs • control from Vserver on PE/GP • shared PE options • shared NP for fast path • shared NP with plugins • 10 GE fabric switch • VLANs used to isolate metarouters • uplinks for connecting to multiple chasses • Good ratio of PEs to LC: 3:1

  6. shared NP blade shared GP blade P L Q . . . S S . . . P L Q LC LC . . . Sharing NPs • Motivation • MRs with limited IO bandwidth can’t make full use of NP blade • extreme (but perhaps common) case – 25 MRs with 100 Mb/s IO • useful to allow such MRs to share a PE • Packet flow • ingress LC terminates external tunnel and adds internal header • MR fast path determines outgoing metalink and queues packet • selected packets directed to Vserver on shared GP blade • injected packets placed on metalink queues in PE • Configuration • single NP blade hosts two shared NPs • each NP engineered for 5 Gb/s throughput • divide TCAM between NPs

  7. ... DeMux Parse Lookup HeaderFormat Shared PE Processing • code constraints • finite, acyclic flow graph • bounded path length • restricted memory accesspacket buffer, control block, output area • thread-safe • inputs (in regs) • buffer pointer • output MI • ctl blk pntr • lookup result pntr • output • buffer offset use MR to find parser code and MR control block header includes MR+MI • Stats module not shown – inputs from DeMux, Lookup and QM. • Potential for plugins using spare MEs • one ME per MR, static SRAM regions, • inputs (in regs) • buffer pointer • MI • ctl blk pntr • output pntr • output • 16B lookup key per metalink queues with static rates • input: MR+lookup key • output: • output MI • qid (supplied by substrate) • lookup result • stats index

  8. Managing MR-Specific Data • MR control software runs on separate PE. • xScale provides interface through control daemon. • enable/disable MR (input packets discarded when disabled) • read/write MR control block • block read/writes to from memory area using offsets • read/write filters • substrate fills in hidden fields (MR in key, qid in result) • read statistics • read/write code segments • cryptographic hash used to verify compliance-checking • only when MR is disabled

  9. Line Card Functions • Substrate functions only • Ingress • terminate tunnels (VLAN, plain IP, IP tunnel, MPLS) • map physical interface + tunnel id + MLI to MR+MI • map MR+MI to destination blade and qid • queue packets in queues with static rates (paced) • provision for xScale to respond to ARP requests • Egress • arriving packets include MR+MI+(next-hop-metanet-adr) • monitor rates for each MR/MI pair – raise alarm if threshold exceeded • if MI is designated as multipoint, • map next-hop-metanet-adr to MAC adr and write into blank spot in buffer • if no matching entry, pass buffer pointer to ARP handler in xScale • xScale handles ARP, fields reply and enqueues packet when reply received • if no reply, send exception notification MR exception interface • place packet in outgoing per-MI queue

  10. Possible Extensions • Queueing in shared PE • allow MR to define multiple queues per MI with queue weights, per queue space allocation and per MI space allocation • substrate implements fair queueing scheduler • WDRR or stratified round-robin • packet discarded if queue using more than its space allocation and more than its share of the shared space • implement when users demand it or spare time available • Limited Plugins • replace Header Formatter with parallel block of MEs, one per MR • code restrictions (static and run-time checks) • access to restricted address ranges • restricted use of bus bandwidth resources • instructions inserted to increment usage counters • xScale (or perhaps dedicated ME) checks counters periodically • MRs using excessive bus bandwidth are disabled

  11. Outline • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • Switch • MetaLink Loopback Block • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  12. Schedule • Two time horizons: • techX Project • End of 2006 • Future Diversified Router Project • Outstanding new grant request under which we do the rest of the work… • JDD’s Proposal: techX End of Year Target: • Data Path • Default IPv4 MR • We should be able to use N instances of this to show multiple MRs running in a Substrate Router. • Legacy PlanetLab nodes in a Blade Server • By Legacy we mean receiving/sending plain IP packets, no Meta/Substrate functionality present. • Basic LC Substrate functionality • IP Tunnel Substrate Link termination • Plain IP handling • MetaLink Loopback Block • Control? • Install an MR • Configure an MR? • Routing Protocols? • Can this be handled through static route configuration? • Etc.? • End Host: • Use Plain IP?

  13. Outline • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • Switch • MetaLink Loopback Block • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  14. Substrate/MetaNet Model Meta Net “A” MR_A MR_A MR_A MI MI MI MI MI MI • The Substrate should provide a view to Meta Nets that their Meta Routers are directly connected via Physical Links • A Meta Interface emulates a Physical Interface • A Meta Link emulates a Physical Link • The Substrate should provide isolation between Meta Nets Meta Net “B” MR_B MR_B MI MI MI MI Meta Net “C” MR_C MR_C MR_C MI MI MI MI MI MI

  15. Substrate/MetaNet Model MetaLink 1 Substrate Link MetaLink 2 MetaLink 3 • Substrate Links connect Substrate Router Peers • A Substrate Link is terminated at a Physical Interface of a Substrate Router. • Meta Links connect Meta Router Peers • A Meta Link is terminated at a Meta Interface on a Meta Router MR_A MR_A MR_A MI MI MI MI MI MI MR_B MR_B MI MI MI MI MR_C MR_C MR_C MI MI MI MI MI MI Substrate Router X Substrate Router Z Substrate Router Y

  16. Mapping the Model onto Hardware Meta Dedicated NP Dedicated GP Shared NP Shared GP Switch LC Loopback Substrate

  17. Mapping the Model onto Hardware • Line Card • Typically supports multiple Physical Interfaces • Our Radisys blade when implementing a LC would have an RTM with 10 1-GE physical interfaces. • Substrate Link Termination • Including IP Tunnel Substrate Link termination • Mux/Demux of Meta Links into/out of Substrate Links. • Pass through Meta Links • Plain IP • Switch • Substrate Switch • Meta Routers on shared blades do not have a view of the switch. • All switching functions are provided by the Substrate • Traffic from all MRs is isolated from other MRs, including dedicated blade MRs, via the use of VLANs • Meta Switch • An MR on a dedicated blade has a view of a Meta-Switch including: • Port its blade is on • Portions of LCs that it has access to. • Loopback (next slide) • NP: Network Processor Blade • GP: General Purpose Processing Blade

  18. Mapping the Model onto Hardware • Line Card • Switch • Loopback • Provides MRx:MIi connectivity to MRy:MIj within Substrate Router • More on this later when we provide details on the components… • NP: Network Processor Blade • Dedicated: entire blade is dedicated to one MR. • No Substrate functionality present. • Shared: blade is shared among several MRs. • Substrate functionality provides resource sharing and isolation • GP: General Purpose Processing Blade • May be realized by a blade in the ATCA chassis or in a blade server directly connected to switch blade which resides in ATCA chassis. • The switch blade has front panel Ethernet interfaces (uplinks) that could be connected to the blade server for this purpose. • Dedicated: entire blade is dedicated to one MR. • No Substrate functionality present. • Shared: blade is shared among several MRs. • Substrate functionality provides resource sharing and isolation.

  19. Legacy Meta MAC Substrate MAC Model: Layering and Abstractions • Two Types of Traffic • Legacy • MAC layer • Legacy Layer (i.e. non-Substrate, typically IPv4) • Substrate • MAC layer • Substrate layer • Meta layer • Figures below are LAYERS, not Packet formats:

  20. Layer Attributes • Attributes at the different layers • Physical/MAC • Type: (Ethernet, ATM, …) • Wireless: (1/0) • Type: (P2P, MA, …) • Substrate • MNid • MRid • MLI • Link Type • Link Model (P2P, Multi-Access) • ARP support • Meta • MetaLink • MI • MnAddr • What is exposed to the MR? • Type: {Ethernet, Wireless, …} • P2P vs. Multi-Access • ARP Provided by Substrate or Not. • ???

  21. Outline • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • Switch • MetaLink Loopback Block • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  22. Traffic at a Substrate Router • For now assume traffic is on wired Ethernet. • Substrate: • EtherType = Substrate • Each frame has a Substrate Header • MLI: Meta Link Identifier • Identifies MR:MI to which this frame should be delivered • Len • Line Card: • sends Meta Frame to the Blade hosting the MR indicated by the MLI • includes in the Meta Header the MR’s MI that this frame is for. • IP: • Other:

  23. Traffic at a Substrate Router • Substrate: • IP: • EtherType = IP • Substrate Tunnels: • IP Proto = Substrate • Each frame has a Substrate Header immediately following IP Header • MLI: Meta Link Identifier • Identifies MR:MI to which this frame should be delivered • Len • Line Card sends Meta Frame to Blade hosting MR indicated by MLI • Included in Meta Header is the MR’s MI that this frame is for. • Plain IP Control Protocols: • Contains no Substrate Header • ICMP • Substrate on LC may need to process some ICMP messages. • ICMP or a subset of ICMP messages sent to XScale on LC. • Depending on processing in Substrate/XScale, ICMP messages may be forwarded on to MR(s). • BGP: Border Gateway Protocol (inter-domain routing protocol) • Treated like Plain IP Data described below: Sent to default IP MR. • OSPF: Open Shortest Path First (intra-domain routing protocol) • Treated like Plain IP Data described below: Sent to default IP MR. • IGMP: Internet Group Management Protocol, used for IPv4 Multicast Group membership • Treated like Plain IP Data described below: Sent to default IP MR. • Other? • Plain IP Data: • Other? • Other:

  24. Traffic at a Substrate Router • Substrate: • IP: • Substrate Tunnels: • Plain IP Control Protocols: • Plain IP Data: • Contains no Substrate Header • Line Card forms Meta Frame and sends it to default IP MR • A unique MI for the default IP MR is associated with each Physical Interface. • Via the default IP MR, plain IP traffic may be destined for: • Other MRs on this Substrate Router via the Loopback • Other MRs on other Substrate Routers via Meta Links carried on Substrate Links • The Default IP MRs on peer Substrate Routers could exchange route information so they know how to get to other Substrate Routers. • Legacy (Pure IP) Planet Lab Nodes on this Substrate Router. • Substrate Control Entities on XScale? • Egress as Plain IP? • Policy based option • Other? • Other: • ARP: • Other?

  25. Outline • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • Switch • MetaLink Loopback Block • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  26. Switch IP Address Assignment Substrate Router(A.B.C.0 – A.B.C.255) PlanetLab Blades X.Y.Z.1 1 U.V.W.1 2 • Consider a Substrate Router (SR) with the following characteristics: • 3 physical interfaces that connect to three Internet Routers: • Interface 1  X.Y.Z.1 • Interface 2  U.V.W.1 • Interface 3  R.S.T.1 • Blade server that contains 6 Legacy (Plain IP) PlanetLab Nodes • A Default IPv4 MR • Block of IP Addresses A.B.C.0 – A.B.C.255 R.S.T.1 3

  27. A.B.C.2 A.B.C.3 A.B.C.4 Switch A.B.C.5 A.B.C.6 A.B.C.7 IP Address Assignment Substrate Router(A.B.C.0 – A.B.C.255) X.Y.Z.1 PlanetLab Blades A.B.C.1 A.B.C.128 X.Y.Z.2 1 U.V.W.1 A.B.C.129 U.V.W.2 2 • Assign addresses to the SR as follows: • Each Physical Interface has a Substrate IP Tunnel Address • Interface 1  A.B.C.128 (A.B.C.0x80) • Interface 2  A.B.C.129 (A.B.C.0x81) • Interface 3  A.B.C.130 (A.B.C.0x82) • Default IPv4 MR has 4 IP Addresses: • To X.Y.Z.1 out Interface 1 : X.Y.Z.2 • To U.V.W.1 out Interface 2 : U.V.W.2 • To R.S.T.1 out Interface 3 : R.S.T.2 • To PlanetLab Nodes: A.B.C.1 R.S.T.1 A.B.C.130 R.S.T.2 3

  28. A.B.C.2 A.B.C.3 A.B.C.4 Switch A.B.C.5 A.B.C.6 A.B.C.7 IP Address Assignment Substrate Router(A.B.C.0 – A.B.C.255) PlanetLab Blades X.Y.Z.1 A.B.C.1 A.B.C.128 X.Y.Z.2 1 U.V.W.1 A.B.C.129 U.V.W.2 2 • Route announcements: • Out Interface 1 • A.B.C.128/32 • A.B.C.0/25 • Out Interface 2 • A.B.C.129/32 • A.B.C.0/25 • Out Interface 3 • A.B.C.130/32 • A.B.C.0.25 R.S.T.1 A.B.C.130 R.S.T.2 3

  29. BGP Notes • RFC 4271: BGP-4 • BGP is defined as an inter-Autonomous System (AS) routing protocol. • Autonomous System: A set of routers under a single technical administration • BGP Speaker: A router that implements BGP • BGP Identifier: an IP Address assigned to a BGP Speaker. Same for every local interface and BGP peer. • A router may also have separate IP Addresses for its interfaces. • UPDATE message used to exchange route information • NEXT_HOP attribute defines IP address of the router that SHOULD be used as the next hop to the destinations listed in the UPDATE message. • Would this potentially be used in ARP requests? • BGP uses TCP between peers. • From RFC 4271, Section 3: • In the context of this document, we assume that a BGP speaker advertises to its peers only those routes that it uses itself (in this context, a BGP speaker is said to “use” a BGP route if it is the most preferred BGP route and is used in forwarding).

  30. Outline • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • MetaLink Loopback Block • Switch • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  31. Meta Link Loopback • We would like to be able to route Plain IP pkts to an MR • We can achieve this by using a default IPv4 MR • But we don’t want the IPv4 MR to have to know anything about other MRs and their Meta-Interfaces • That is a Substrate function • So, we need a Substrate function to translate from • MRx:MIi to MRy:MIj • We would also like to be able to route Plain IP pkts to Legacy PlanetLab Nodes residing on Blades in a Substrate Router • Legacy PlanetLab Nodes have no Substrate. • Again we can use the default IPv4 MR to achieve this. • But the packets cannot have a Substrate Header or Meta Header when they arrive at the PlanetLab Nodes. • So, we need a Substrate function to strip these headers. • We would also like to be able to do similar things with IP Pkts in Substrate Frames on MetaLinks which terminate at the default IPv4 MR • We will implement a Meta Link Loopback block • Provides Internal Meta Link Loopbacks at the Substrate level. • Probably will reside on one or more Line Cards.

  32. Meta Link Loopback Physical interface ‘n’ on LC A Substrate Router Def IPv4 MR LC A n m Physical interface ‘m’ on LC A MR Y n LC B Physical interface ‘n’ on LC B MR X Loopback PLab Switch

  33. Meta Link Loopback: Plain IP to/from MR Y Substrate Router Def IPv4 MR IPAm IP VLAN ‘a’ used. IPBn a IP LC A Ab : MI b associated with MR A used n IPYk IP m Plain IP IPAm IP MR Y Yk n IPBn Plain IP Y LC B IP MR X Loopback IPYk IP Yk Y PLab Switch

  34. Meta Link Loopback: Plain IP to/from PLab Substrate Router Def IPv4 MR IPAm IP VLAN ‘a’ used. IPBn a IP IPPi IP LC A Ab : MI b associated with MR A used n m Plain IP IPAm IP MR Y n IPBn Plain IP LC B IP MR X IPPi Loopback Plain IP PLab P Plain IP P Switch

  35. Meta Link Loopback: General IPAn Substrate Router IP Def IPv4 MR IPAm IP VLAN ‘a’ used. IPBn a IP IPPi IP LC A IPXj Ab : MI b associated with MR A used n Substrate IPAn IP IPYk IP IP m Plain IP IPAm IP MR Y Yk n IPBn Plain IP Y LC B IP MR X Xj X IPPi IP Loopback IPXj IPYk Yk Y Xj X Plain IP PLab P Plain IP P Switch

  36. Outline • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • MetaLink Loopback Block • Switch • NP Blades • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  37. Switch • Switch Blade Specs: • Promentum™ ATCA-2210 • http://www.radisys.com/products/ds-page.cfm?productdatasheetsid=1191 • 20-port 10GE fabric switch • 14 10GE links to user slots • 4 10GE links for external connections (up/cross links) on front panel • 24-port 1GE Base switch • 14 1GE links to users lots • 1GE link to redundant switch blade • 1 10GE and 4 1GE links for external connections (up/cross links) on front panel • Wire-speed L2 and L3 switching • 4K IEEE 802.1Q VLANs • Etc… • Traversing the Switch: • Switching is based on Ethernet Destination Address • Isolation is based on VLAN. • One VLAN will be assigned to each MetaNet present on a Substrate Router. • All switch traffic for a MetaNet will be required to use its assigned VLAN. • Frames from a MetaNet will only be transmitted to a port which is allowed to receive the specified VLAN.

  38. Outline • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • MetaLink Loopback Block • Switch • NP Blades • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  39. NP Blades: Radisys 7010

  40. NP Blades: Radisys 7010 10Gb Per Port Ethernet Switch Blade ATCA Backplane 16 / FIC NPUA SPI-4 Switch / 16 1 / 10G MAC 10Gb Per Port Ethernet Switch Blade / 1 16 / NPUB / 16 • SPI-4 Switch supports 6 Interfaces • Each Interface can support up to 16 SPI-4 Ports • Each Port on an Interface can be switched to any other Port on any other Interface • Radisys 7010 uses 4 of the 6 Interfaces • 10G MAC Chip (IXF18105) supports and uses only 1 SPI-4 Port on its SPI-4 Interface • Therefore, all traffic from 10G MAC Chip must go to one NPU, either NPUA or NPUB. • This should be fine for our LC in the future • One NPU will be for Ingress and one for Egress • For our NPE Blades, this will be a bit of pain. • We can direct all traffic to NPUA and then have a block right after RX that splits the traffic for NPUA and NPUB • Traffic for NPUA continues on to the processing blocks on NPUA • Traffic for NPUB would go directly to a TX block to be transmitted to NPUB via the SPI Switch. (Does not go to 10G MAC chip) • Still need to work out whether this will actually work or not.

  41. NP Blades: Radisys 7010 • Radisys 7010 • Two IXP2850 NPs • 1.4 GHz Core • 700 MHz Xscale • Each with: • 3x256MB RDRAM, 533 MHz • 3 Channels of QDR II SRAM, 8MB each, 200 MHz • 16KB of Scratch Memory • 16 Microengines • 8KB instruction store • 640 32-bit words of local memory • Network Search Engine on 4th QDR channel • Shared between NPs • IDT75K72234 • 18Mb TCAM • SPI-4 Switch for interconnections

  42. Line Cards : Radisys 7010 with RTM • Radisys 7010 with RTM • Same board as NP blade. • Two IXP2850 NPs • One used for Ingress • One used for Egress • Rear Transition Module (RTM) • Connects via ATCA Zone 3 • 10 1GE Physical Interfaces • Supports Fiber or Copper interfaces.

  43. Radisys 7010 Blade

  44. Outline • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • Switch • MetaLink Loopback Block • LC • Substrate Link Types • Packet Formats • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  45. Substrate Links • 2 Types of Substrate Links: • Point-to-Point (P2P) • Connects two peer Substrate Routers • May be realized via: • Directly Connected (P2P-DC) • One physical link connects an Interface on one Substrate Router to an Interface on another Substrate Router • Can use VLANs or not. • Tunnel (P2P-Tunnel) • Two Substrate Routers have a Tunnel defined that connects an interface on each router. • Such a tunnel comprises exactly one Substrate Link. • Can use VLANs or not. • Multi-Access Network (P2P-VLAN0) • Substrate Routers with interfaces connected to a Multi-Access Network all use a predefined VLAN (VLAN0). • VLAN0 is defined for each Multi-Access Network and my be different on each one. • Each of these Substrate Routers is pre-configured with the Ethernet addresses of the other Substrate Routers connected to the Multi-Access Network. • By using the Ethernet address of peers, pairs of Substrate Routers have defined Substrate Links. • With N Substrate Routers, there are at most (N*(N-1))/2 Substrate Links • Multi-Access

  46. Substrate Links • 2 Types of Substrate Links: • Point-to-Point (P2P) • Multi-Access • Supports Unicast, Multicast and Broadcast traffic from Meta Routers. • Interfaces on Substrate Routers connected to a Multi-Access network are NOT necessarily pre-configured with each others Ethernet addresses. • ARP may be used over the Multi-Access network to do the translation from MetaNet Address to Ethernet Address. • ARP protocol and tables are managed by XScale. • Can use VLANs or not, but cannot use VLAN0.

  47. Substrate Links • Substrate Link Restrictions: • P2P-DC does not co-exist on a physical interface with any of the other types of SL. • P2P-Tunnel, P2P-VLAN0 and Multi-Access may all co-exist on the same physical interface. • A physical interface may have: • At most one P2P-DC SL • XOR • One or more P2P-Tunnel SLs • One or more P2P-VLAN0 SLs • At most one Multi-Access SLs

  48. IP Tunnel Substrate Links • Each IP Tunnel Substrate Link is terminated at a single Physical Interface on a Substrate Router. • The only route TO this end of the tunnel is from the outside into the associated physical interface. • Nothing inside the Substrate Router routes TO this end of the Tunnel • From inside the Substrate Router packets are just sent INTO the tunnel so they come out the other end. • Included in the configuration of an IP Tunnel Substrate Link is the Address (IP or MAC?) of the next/first hop for the route to the other end of the tunnel. • What happens if the routes in the Internet change and this next/first hop is no longer the way to go? • Physical Interface will receive ICMP No Route to Host or ICMP Redirect messages. • ICMP messages should be sent to the XScale on the Line Card. • XScale should then nullify (mark as down, …) the IP Tunnel Substrate Link and all MetaLinks/MetaInterfaces associated with that Substrate Link.

  49. Outline • JST’s original slides • Schedule • Model • Traffic Types • IP Addressing • Components • Switch • MetaLink Loopback Block • LC • Substrate Link Types • Packet Formats • Focus is on wired Ethernet • LC Rx/Tx Design Implementation • Common Router Framework (CRF) • Functional Blocks for implementing a Router

  50. P2P-DC SL Packet With VLANs P2P-DC SL Packet Without VLANs DstAddr (6B) SrcAddr (6B) DstAddr (6B) Type=802.1Q (2B) SrcAddr (6B) TCI (2B) Type=Substrate (2B) Type=Substrate (2B) MLI (2B) MLI (2B) LEN (2B) LEN (2B) Meta Frame Meta Frame PAD (nB) PAD (nB) CRC (4B) CRC (4B) Point-to-Point Directly Connected (P2P-DC) LC LC MR MR MetaLinks MR MR • P2P should not need the Type=Substrate since it is a point-to-point physical link and should only be carrying Substrate traffic. • Configuration/Policy/Implementation option?

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