摘要:
Routes may be installed across multiple link state protocol controlled Ethernet network areas by causing ABBs to leak I-SID information advertised by BEBs a L1 network area into an L2 network area. ABBs will only leak I-SIDs for BEBs where it is the closest ABB for that BEB. Where another ABB on the L2 network also leaks the same I-SID into the L2 network area from another L1 network area, the I-SID is of multi-area interest. ABBs will advertise I-SIDs that are common to the L1 and L2 networks back into their respective L1 network. Within each L1 and L2 network area, forwarding state will be installed between network elements advertising common interest in an ISID, so that multi-area paths may be created to span the L1/L2/L1 network areas. ABBs may summarize BEB multicast trees such that the set of trees for a given I-SID transiting the ABB is condensed into a common tree. The L2 network may further be implemented as a second layer implemented using a L1/L2/L1 network structure, so that the L1/L2/L1 network structure may recurse an arbitrary number of times.
摘要:
Routes may be installed across multiple link state protocol controlled Ethernet network areas by causing ABBs to leak I-SID information advertised by BEBs in a L1 network area into an L2 network area. ABBs will only leak I-SIDs for BEBs where it is the closest ABB for that BEB. Where another ABB on the L2 network also leaks the same I-SID into the L2 network area from another L1 network area, the I-SID is of multi-area interest. ABBs will advertise I-SIDs that are common to the L1 and L2 networks back into their respective L1 network. Within each L1 and L2 network area, forwarding state will be installed between network elements advertising common interest in an ISID, so that multi-area paths may be created to span the L1/L2/L1 network areas. The L1/L2/L1 network structure may recurse an arbitrary number of times.
摘要:
Routes may be installed across multiple link state protocol controlled Ethernet network areas by causing ABBs to leak I-SID information advertised by BEBs in a L1 network area into an L2 network area. ABBs will only leak I-SIDs for BEBs where it is the closest ABB for that BEB. Where another ABB on the L2 network also leaks the same I-SID into the L2 network area from another L1 network area, the I-SID is of multi-area interest. ABBs will advertise I-SIDs that are common to the L1 and L2 networks back into their respective L1 network. Within each L1 and L2 network area, forwarding state will be installed between network elements advertising common interest in an ISID, so that multi-area paths may be created to span the L1/L2/L1 network areas. The L1/L2/L1 network structure may recurse an arbitrary number of times.
摘要:
Multicast capabilities of a link state protocol controlled network are used to accelerate the flooding advertisement of topology change notifications within portions of the network. This flooding mechanism may be particularly efficient in a network with a large number of two-connected nodes such as a ring network architecture. A control plane specific multicast group address is used when flooding topology change notifications, and a process such as reverse path forwarding check is used as an additional control on forwarding of the notification to prevent looping of control plane packets. Two-connected nodes insert a forwarding entry into their FIB to enable frames containing the control message to be forwarded via the data plane on to the downstream node so that propagation of the control message along a chain of two-connected nodes may occur at data plane speeds.
摘要:
Multicast capabilities of a link state protocol controlled network are used to accelerate the flooding advertisement of topology change notifications within portions of the network. This flooding mechanism may be particularly efficient in a network with a large number of two-connected nodes such as a ring network architecture. A control plane specific multicast group address is used when flooding topology change notifications, and a process such as reverse path forwarding check is used as an additional control on forwarding of the notification to prevent looping of control plane packets. Two-connected nodes insert a forwarding entry into their FIB to enable frames containing the control message to be forwarded via the data plane on to the downstream node so that propagation of the control message along a chain of two-connected nodes may occur at data plane speeds.
摘要:
Routes may be installed across multiple link state protocol controlled Ethernet network areas by causing ABBs to leak I-SID information advertised by BEBs a L1 network area into an L2 network area. ABBs will only leak I-SIDs for BEBs where it is the closest ABB for that BEB. Where another ABB on the L2 network also leaks the same I-SID into the L2 network area from another L1 network area, the I-SID is of multi-area interest. ABBs will advertise I-SIDs that are common to the L1 and L2 networks back into their respective L1 network. Within each L1 and L2 network area, forwarding state will be installed between network elements advertising common interest in an ISID, so that multi-area paths may be created to span the L1/L2/L1 network areas. ABBs may summarize BEB multicast trees such that the set of trees for a given I-SID transiting the ABB is condensed into a common tree. The L2 network may further be implemented as a second layer implemented using a L1/L2/L1 network structure, so that the L1/L2/L1 network structure may recurse an arbitrary number of times.
摘要:
Multicast capabilities of a link state protocol controlled network are used to accelerate the flooding advertisement of topology change notifications within portions of the network. This flooding mechanism may be particularly efficient in a network with a large number of two-connected nodes such as a ring network architecture. A control plane specific multicast group address is used when flooding topology change notifications, and a process such as reverse path forwarding check is used as an additional control on forwarding of the notification to prevent looping of control plane packets. Two-connected nodes insert a forwarding entry into their FIB to enable frames containing the control message to be forwarded via the data plane on to the downstream node so that propagation of the control message along a chain of two-connected nodes may occur at data plane speeds.
摘要:
Nodes on an Ethernet network run a link state protocol on the control plane and install shortest path forwarding state into their FIBs to allow packets to follow shortest paths through the network without requiring MAC header replacement at each hop through the network. When a node learns an IP address, it will insert the IP address into its link state advertisement to advertise reachability of the IP address to the other nodes on the network. Each node will add this IP address to its link state database. If a packet arrives at an ingress node, the ingress node will read the IP address, determine which node on the link state protocol controlled Ethernet network is aware of the IP address, and construct a MAC header to forward the packet to the correct node. The DA/VID of the MAC header is the nodal MAC of the node that advertised the IP address. Unicast and multicast IP forwarding may be implemented.
摘要:
Nodes on a link state protocol controlled Ethernet network implement a link state routing protocol such as IS-IS. Nodes assign an IP address or I-SID value per VRF and then advertise the IP addresses or I-SID values in IS-IS LSAs. When a packet is to be forwarded on the VPN, the ingress node identifies the VRF for the packet and performs an IP lookup in customer address space in the VRF to determine the next hop and the IP address or I-SID value of the VRF on the egress node. The ingress node prepends an I-SID or IP header to identify the VRFs and then creates a MAC header to allow the packet to be forwarded to the egress node on the link state protocol controlled Ethernet network. When the packet is received at the egress node, the MAC header is stripped from the packet and the appended I-SID or IP header is used to identify the egress VRF. A customer address space IP lookup is then performed in the identified VRF on the egress node using the information in the client IP header to determine how to forward the packet. Customer reachability information within a VPN may be exchanged between VRFs using iBGP, or directly by using link state protocol LSAs tagged with the relevant I-SID.
摘要:
Nodes on a link state protocol controlled Ethernet network implement a link state routing protocol such as IS-IS. Nodes assign an IP address or I-SID value per VRF and then advertise the IP addresses or I-SID values in IS-IS LSAs. When a packet is to be forwarded on the VPN, the ingress node identifies the VRF for the packet and performs an IP lookup in customer address space in the VRF to determine the next hop and the IP address or I-SID value of the VRF on the egress node. The ingress node prepends an I-SID or IP header to identify the VRFs and then creates a MAC header to allow the packet to be forwarded to the egress node on the link state protocol controlled Ethernet network. When the packet is received at the egress node, the MAC header is stripped from the packet and the appended I-SID or IP header is used to identify the egress VRF. A customer address space IP lookup is then performed in the identified VRF on the egress node using the information in the client IP header to determine how to forward the packet. Customer reachability information within a VPN may be exchanged between VRFs using iBGP, or directly by using link state protocol LSAs tagged with the relevant I-SID.