Double EXP QoS Markings for MPLS Packets
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Solution Overview
Problem
Conventional Multiprotocol Label Switching (MPLS) networks lose quality of service (QoS) resolution due to the mapping of Differentiated Services Code Point (DSCP) markings to a single experimental (EXP) field, resulting in inadequate treatment of mission-critical and best-effort traffic, especially in scenarios where RSVP-TE is not provisioned.
Innovation Solution
Edge routers in MPLS networks map DSCP markings to at least two EXP fields across multiple labels in the MPLS header, enabling full QoS resolution by combining the first and second EXP fields to identify the correct QoS profile for forwarding packets, thereby maintaining end-to-end QoS across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If DSCP markings are mapped to a single EXP field in MPLS packets, then the mapping process is simple, but QoS resolution is lost and inadequate treatment of traffic classes occurs
Solution Approach 1:
The patent segments the single EXP field mapping into multiple EXP fields (first EXP field and second EXP field) across different labels in the MPLS header. This segmentation allows the six-bit DSCP marking to be mapped to six bits distributed across two three-bit EXP fields, thereby preserving full QoS resolution while maintaining manageable complexity in the mapping process.
2Measurement precision
If multiple EXP fields are used to maintain QoS resolution, then full QoS resolution is achieved, but the device complexity increases
Solution Approach 1:
The patent transitions from a single-dimension mapping (one EXP field) to a multi-dimensional mapping structure by utilizing multiple labels in the MPLS header. Each label contains an EXP field, and the combination of these EXP fields across different label dimensions provides the additional bits needed for full QoS resolution without requiring a single complex field.
3Speed
If conventional single EXP field mapping is used, then the forwarding process is fast, but mission-critical and best-effort traffic receive inadequate treatment
Solution Approach 1:
The patent segments the QoS marking information across multiple EXP fields in different labels, allowing core routers to read and process the first EXP field for fast forwarding decisions while the combination of first and second EXP fields provides reliable QoS treatment classification. This segmentation enables both speed and reliability by distributing the QoS information across multiple fields.
Data Source
AI summary
Techniques are described for applying double experimental (EXP) quality of service (QoS) markings to Multiprotocol Label Switching (MPLS) packets. According to the techniques, an edge router of an MPLS network is configured to map a Differentiated Services Code Point (DSCP) marking for customer traffic to at least two EXP fields of at least two different labels included in a MPLS packet encapsulating the customer traffic. In this way, the edge router may map the full DSCP marking across the first and second EXP fields to provide full resolution QoS for the customer traffic over the MPLS network. The techniques also include a core router of an MPLS network configured to identify a QoS profile for a received MPLS packet based on a combination of a first EXP field of a first label and a second EXP field of a second label included in the MPLS packet.