Managing interdomain traffic in Latin America: a new perspective based on LISP

An Approach to a Fault Tolerance LISP Architecture

“…LISP does not specify a mandatory mapping system, and as a consequence, different proposals can be found in the recent literature, such as ALT [15], NERD [16] or Map Server [17]. Besides, in [18] we introduced a new control plane for LISP; the new control plane presents an improvement on three aspects respect to the existing solutions; (i) firstly, -First packets drop problem‖ when an ITR does not have a mapping for an EID-prefix; (ii) secondly, potential increase in the latency to start a communication due to the mapping resolution; and (iii) in order to avoid a two-way mapping resolution, the ITR is used as the local ETR for the packets sent from D to S. The latter introduces limitations in terms of inbound Traffic Engineering, especially, when outbound and inbound traffic policies do not match. Despite these improvements there are other issues relating to reachability and reliability that have not been resolved, such as those motivated by an inter-domain link failure.…”

“…When the packet reaches a border router (step 2) that has no corresponding mapping, this router makes a broadcast to other LRP Groups of the packets that are arriving (step 3), and in turn, the LRP Group sends a Map-Request to the LCB (step 4) that is responsible for handling all mappings within an AS. A LCB (LISP Control Box) is an entity introduced in [18] responsible of all mappings within an AS which might be a standalone device or run as an instance of a PCE. The LRP Group that owns the required mapping, sends it via unicast to the LRP Group responsible for these packages (requester) (step 5), and encapsulates and forwards the traffic.…”

“…In [18] authors propose a new LISP control plane, aimed to overcome the issues derived by current mapping systems such as ALT, CONS or NERD. The main issue behind these approaches is related to the first packet drop problem, which refers to the mapping resolution for a prefixed EID for the first outgoing packet, this also derives in the potential increase in the latency to start a communication.…”

“…This newly proposed control plane is based on the idea of retrieving EID-to-RLOC mappings within the DNS Resolution time. A major shortcoming of the solution proposed in [18] is that the mappings between EIDs and RLOCs are replicated in all of the edge routers within the same AS. Despite the fact that this option ensures improved reachability, unfortunately it may bring scalability problems since each router must store mapping information that rarely needs to use (i.e.…”

“…In this scenario, border routers can be members of different groups, and the "key" difference between LRP and HSRP focuses on the fact that LRP enables a router to be Slave in a group and Master in another (see Figure 4). By implementing this feature all routers can be in forwarding mode, hence overcoming the limitation present in [18], namely to avoid the need of replicating the entire mapping on all the border routers. In case of either a link or border router failure, the last one will interchange his mapping with the border router that is now responsible of handling the traffic in this logical group.…”