The use and application of SR MPLS is increasing and it’s easy to see why. The source-routing architecture that achieves the right balance between distributed intelligence and centralized optimization brings many advantages to enterprises. And Huawei’s SRv6 is one step beyond this ample functionality by providing complete control over the forwarding paths by combining simple network instructions.
WHAT IS SRv6?
SRv6 stands for Segment Routing over IPv6 dataplane. SRv6 is a new extension directly in the IPv6 IP extension header. This extension is called SRH (Segment Routing Header), which is used to program and combine segments to form SRv6 paths.
ENCAPSULATION FORMAT OF SRv6 PACKETS
HOW ARE SRv6 PACKETS FORWARDED?
SRH is directly extended from the header of an IPv6 packet, which means that a device that supports IPv6 packet forwarding can also forward SRv6 packets, but in this case, it will ignore this header extension.
Segment routing does not require any path signaling. Hence, per-flow state only needs to be maintained at the ingress node of the SR domain increasing your network flexibility while reducing cost.
In other words, Segment Routing runs natively on an MPLS or IPv6 data plane. A simple software upgrade will enable your hardware to run it. Also, Segment Routing can coexist with your existing LDP network, making the migration painless.
When a device that supports SRv6 forwarding receives an SRv6 packet, it looks up the local Local SID table according to the outer IPv6 address and executes the hit instruction action. At the same time, it copies the SID of segments left to the outer IPv6 header. Destination address. When SL = 0, the SRH extended header pops up and becomes a normal IPv6 packet for forwarding.
WHAT ARE THE ADVANTAGES OF SRv6?
Enterprises that have to deal with high traffic stand to gain a lot from implementing SRv6. They can use Segment Routing to steer traffic along any arbitrary path in the network. This allows operators to enforce low-latency and / or disjoint paths, regardless of the normal forwarding paths.
Since SRv6 is compatible with IPv6 routing and forwarding, it does not need to introduce extra signaling like MPLS, and it also requires network-wide upgrade.
Based on SRH, it can support more types of packaging, which can well meet the diversified needs of new services. What’s more - SR achieves this without any additional signaling or midpoint fabric-state!
SRv6's affinity for IPv6 enables it to seamlessly integrate IP bearer networks with applications that support IPv6. Through network-aware applications, it can bring more possible value-added to operators.
Since SRv6 is capable of creating inter-domain policies. It enables enterprises to take advantage of the path-expressivity while keeping your DC, Metro and WAN domains independent. The SRv6 capability of Segment Routing allows user-defined functions to be associated with segments. By leveraging the SRv6 and the dedicated Segment Routing Extension Header, these functions may implement any computable behavior allowing for Network Function Virtualization.
More and more enterprises roll out SRv6 in live networks due to its commercial traffic, multiple interoperable linerate multiTbps hardware, with a rich open-source eco-system and capacity for a standardization process. This clearly exemplifies SRv6 maturity and its ability to meet all expressed requirements.
All in all, SRv6 is a huge step from SR MPLS. It not only has routing capabilities, but exhibits ample functionality way beyond what SR MPLS is capable of. SRv6 is aggregatable, it is programmable, it is globally unique over a larger scope. Its routing capabilities bring many benefits to the enterprise network. For example: network scalability, reliability, and simplified Overlay programming.
Since 2019, SRv6 has been gaining significant enterprise traction with noteworthy live deployments and adoption is growing at pace. One of the major benefits of the SRv6 NPC is the seamless deployment, as no massive hardware/software upgrade is required in an IPv6 network. And since IPv6 connectivity is getting more pervasive, SRv6 is the next logical step building on SR MPLS capabilities.
SRv6 further simplifies the network by eliminating MPLS altogether and by relying on the native IPv6 header and header extension to provide the same services and flexibility as SR-MPLS, directly over the IPv6 data plane.
THE BOTTOM LINE
Enterprises across different sectors are finding that Srv6 adoption is producing remarkable results with some noteworthy live deployments supporting significant customer traffic. Corporations that aim to further enhance the efficiency and functionality of their networks are introducing the latest technologies such as SRv6 with the intent to roll out a highly reliable mobile network that can cope with the future traffic for the age of 5G and IoT.
And it doesn’t stop there. In the next coming months, we are bound to hear about more enterprises taking advantage of SRv6’s opportunities.
