1 / 20

BGPv4 SAFI-Specific Attribute draft-kapoor-nalawade-idr-bgp-ssa-00.txt

BGPv4 SAFI-Specific Attribute draft-kapoor-nalawade-idr-bgp-ssa-00.txt. Ruchi Kapoor ruchi@cisco.com Gargi Nalawade gargi@cisco.com Chandrashekhar Appanna achandra@cisco.com. Problem description. Tunnel configuration O(N^2)

hachi
Download Presentation

BGPv4 SAFI-Specific Attribute draft-kapoor-nalawade-idr-bgp-ssa-00.txt

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. BGPv4 SAFI-Specific Attributedraft-kapoor-nalawade-idr-bgp-ssa-00.txt Ruchi Kapoor ruchi@cisco.com Gargi Nalawade gargi@cisco.com Chandrashekhar Appanna achandra@cisco.com

  2. Problem description • Tunnel configuration O(N^2) • Need a dynamic mechanism of exchanging Tunnel endpoint information, inter and intra-AS • For a BGP-learnt route, Tunnel endpoint has one-to-one correspondence with the BGP next hop • Traffic to that destination can be Tunnel-switched or IP-switched

  3. The Solution • A New SAFI to advertise the Tunnel endpoint information • A New attribute to encode TLVs of Tunnel Encapsulation Capabilities

  4. BGPv4 SAFI-Specific Attributedraft-kapoor-nalawade-idr-bgp-ssa-00.txt Ruchi Kapoor ruchi@cisco.com Gargi Nalawade gargi@cisco.com Chandrashekhar Appanna achandra@cisco.com

  5. The SAFI-Specific Attribute (SSA) • Today the Tunnel application needs a BGP Attribute that can encode a set of TLVs and sub-TLVs inside it • The need for a simple and flexible encoding for carrying a TLV-set exists • The SAFI-Specific Attribute gives the ability to encode such TLV-sets on an as-needed basis.

  6. The SSA Encoding 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|1|0|?|UNUSED | Type = TBD | Length (2 Octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Attribute Value | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  7. The SSA Value field • The Value field contains a set of one or more TLVs of the following form : 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |T| Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ • The Value will contain a set of Fixed fields • May contain optional Sub-TLVs after the fixed Value

  8. The TLV Type-codes • A SAFI that wants to use this attribute will have to specify the Type-codes it recognizes • The Type of the TLV will be a global space irrespective of what SAFI or application defines it

  9. Operational details • The attribute defined as Optional Transitive • No Capability defined for this attribute • For new SAFIs that want to use this, presence of the SAFI indicates understanding of the attribute • Forward compatibility • Experimental Typecode space • Open for suggestion on a better name

  10. The Tunnel SAFIdraft-nalawade-kapoor-tunnel-safi-00.txt Gargi Nalawade gargi@cisco.com Ruchi Kapoor ruchi@cisco.com Dan Tappan tappan@cisco.com

  11. The Tunnel SAFI • The Tunnel endpoint address will be the NLRI in this SAFI • The Tunnel Encapsulation Capabilities will be carried in the BGPv4 SAFI-Specific Attribute in the form of a set of one or more TLVs

  12. The Tunnel SAFI NLRI • The NLRI for the IPv4 Tunnel SAFI will be a 2-octet Reserved field followed by the IPv4 address of the Tunnel endpoint • The Reserved field to contain a 2-octet Identifier that identifies • a Tunnel and • a set of Prefixes that want to use the Tunnel

  13. The Tunnel SAFI NLRI (contd.) • The NLRI containing the Tunnel endpoint address, expected to do the binding between a set of BGP routes in other SAFIs and the Tunnel Encapsulation information carried by this SAFI • The 2-octet Identifier could be carried as • Part of the Nexthop using MP Nexthop • Part of the SNPA in the Nexthop • Part of a community

  14. TLV Type-code definitions • This SAFI defines the following Typecodes for the Tunnel Encapsulation Capabilities • Type 1 : L2TPv3 Tunnel information • Type 2 : mGRE Tunnel information • Type 3 : IPSec Tunnel information • Type 4 : MPLS Tunnel information

  15. L2TPv3 Tunnel TLV • The L2TPv3 Tunnel TLV looks as follows 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 0x01 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length (2 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Preference (2 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S| Flags | Cookie Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session ID (4 Octets) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Cookie (Variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  16. L2TPv3 Tunnel TLV (contd.) • The fixed fields defined in the TLV can be followed by one or more sub-TLVs of the form 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Value (Variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  17. mGRE Tunnel TLV • The mGRE Tunnel TLV looks as follows 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 0x02 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length (2 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Preference (2 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S|K| Flags | | +-+-+-+-+-+-+-+-+ | | mGRE Key (4 Octets) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  18. mGRE Tunnel TLV (contd) • The Fixed fields in the mGRE Tunnel TLV may also be followed by a set of one or more sub-TLVs

  19. Capability • A BGP Speaker must advertise the MP_EXT Capability with this AFI-SAFI pair, in order to speak this SAFI • Use of this SAFI implies understanding of the SSA Attribute and at least one Tunnel Encapsulation TLV as specified by this SAFI

  20. Conclusion • A New SAFI to provide • isolation of Tunnel information from other existing SAFIs • optimum amount of information advertised • The NLRI encoding help conserves address-space when using multiple Tunnels • A New Attribute • That can carry a set of TLVs • Flexible and adaptive to future extensions

More Related