VXLAN Tunnel Reachability via Inter-Chassis Link Default Egress Object
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Solution Overview
Problem
In VXLAN networks, particularly those using Broadcom routers, the restriction of one-to-one egress port to next hop mapping limits the ability to reach multiple remote VTEPs through inter-chassis links, causing traffic tromboning and significant latency, which negatively impacts network performance.
Innovation Solution
Implementing a multiple tunneling process that creates a default egress object on the inter-chassis link with a next hop defined as a VLT peer, allowing multiple VXLAN tunnels to be reachable with an optimal path to all next hops by setting the MAC address of the VLT peer and using a spanned VLAN, thereby avoiding traffic tromboning and sub-optimal paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one-to-one egress port to next hop mapping is used in Broadcom routers, then device complexity is reduced and mapping is simplified, but the ability to reach multiple remote VTEPs through inter-chassis links is limited, causing traffic tromboning and increased latency
Solution Approach 1:
The patent segments the egress port mapping by introducing a separate ICL egress object that is shared across multiple next hops. Instead of each next hop having its own dedicated egress port mapping, the ICL egress object is segmented to serve multiple VTEPs simultaneously, allowing multiple remote VTEPs to be reached through the same inter-chassis link without tromboning.
Solution Approach 2:
The ICL egress object is designed with multi-functionality to serve multiple purposes: it handles traffic to multiple remote VTEPs, supports both VLT and non-VLT peer scenarios, and provides a universal solution for inter-chassis communication. This universal egress object replaces the need for separate dedicated mappings for each next hop.
2Productivity
If multiple VXLAN tunnels are made reachable through inter-chassis links, then network performance is improved and latency is reduced, but the one-to-one mapping restriction of Broadcom routers must be overcome
Solution Approach 1:
The patent introduces an intermediary ICL egress object that mediates between multiple next hops and the inter-chassis link. This intermediary object acts as a bridge, allowing multiple VTEPs to share the same egress port without requiring complex one-to-one mappings. The intermediary simplifies the overall mapping structure while enabling multiple tunnels.
Solution Approach 2:
Multiple next hop mappings are merged into a single shared ICL egress object. Instead of maintaining separate mappings for each VTEP, the patent combines them into one unified egress object that handles traffic to all remote VTEPs through the inter-chassis link, reducing mapping complexity while improving performance.
3Adaptability or versatility
If traffic tromboning occurs through data center backhaul, then routing flexibility is maintained, but significant latency (30-80 milliseconds) is added to network communication
Solution Approach 1:
The patent introduces dynamic path selection by making the ICL egress object conditional based on VLT topology detection. When VLT peers are detected, the system dynamically switches to the direct ICL path, avoiding tromboning. When VLT peers are not present, it falls back to traditional routing. This dynamic adaptation eliminates unnecessary latency while maintaining routing flexibility.
Solution Approach 2:
The system performs preliminary detection of VLT peer relationships before establishing traffic paths. By detecting VLT topology in advance and pre-configuring the shared ICL egress object, the system can immediately route traffic optimally without undergoing tromboning, thus preventing latency before it occurs.
Data Source
AI summary
Embodiments are directed to facilitate multiple tunnels to be reachable via inter-chassis ling from virtual link trunking (VLT) peers and also to avoid traffic tromboning with an optimal path to all next hops. During initialization, a default egress object is created through an ICL with the next hop defined as VLT peer2 by setting the MAC address to be the MAC address of the VLT peer2, and the VLAN to be any one of the L3 spanned VLANs. When any of the VXLAN tunnels are resolved through ICL LAG, the process uses the default egress object created on ICL. Using the default egress object created on ICL, any traffic from VLT peer1 intended to go through ICL is terminated on VLT peer2 and will get routed again to their respective next hops. This creates a single egress object to the VLT peer and allowing multiple VXLAN tunnels to be reachable through ICL with optimal path towards all next hops.