Basic Principles of Seamless MPLS - Part 2

Inter-AS Seamless MPLS

Control plane 

  Deploy routing protocols:

Figure 1 Deploying routing protocols for the inter-AS seamless MPLS networking

As shown in Figure 1, routing protocols are deployed on devices as follows:

• An IGP (IS-IS or OSPF) is enabled on devices at each of the access, aggregation, and core layers to implement intra-AS connectivity.
• The path CSG1 -> AGG1 -> AGG ASBR1 -> core ASBR1 -> MASG1 is used in the following example. A BGP peer relationship is established between each of the following pairs of devices:

  • CSG and AGG
  • AGG and AGG ASBR
  • AGG ASBR and core ASBR
  • Core ASBR and MASG
  An EBGP peer relationship is established between the AGG ASBR and core ASBR, and IBGP peer relationships are established between other devices.
• The AGG is configured as an RR so that IBGP peers can exchange BGP routes, and the CSG and MASG can obtain BGP routes destined for each other's loopback addresses.
• If the AGG ASBR and core ASBR are connected indirectly, an IGP neighbor relationship between them must be established to implement inter-area connectivity.

Deploy tunnels:

Figure 2 Deploying tunnels for the inter-AS seamless MPLS networking

As shown in Figure 2, tunnels are deployed as follows:

• A public network tunnel is established using LDP or TE in each IGP area. An LDP LSP or a TE LSP is established if more than one hop exists between the AGG ASBR and core ASBR.
• The CSG, AGG, AGG ASBR, and core ASBR are enabled to advertise labeled routes and assign labels to BGP routes that match a specified routing policy. After the devices exchange labeled BGP routes, a BGP LSP is established between the CSG and core ASBR.
• Either of the following tunnel deployment methods can be used in the core area:

  • A BGP LSP between the core ASBR and MASG and combined with the BGP LSP between the CSG and core ASBR to form an E2E BGP LSP. The route to the MASG's loopback address is installed into the BGP routing table and advertised to the core ASBR using the IBGP peer relationship. The core ASBR assigns a label to the route and advertises the labeled route to the AGG ASBR.
  • No BGP LSP is established between the core ASBR and MASG. The core ASBR runs an IGP to learn the route destined for the MASG's loopback address and installs the route to the routing table. The core ASBR assigns a BGP label to the route and associates the route with an intra-AS tunnel. The BGP LSP between the CSG and core ASBR and the MPLS tunnel in the core area are combined into an E2E tunnel.

  
  

Forwarding plane

Figure 3 Forwarding plane for the inter-AS seamless MPLS networking with a BGP LSP established in the core area

Figure 3 illustrates the forwarding plane of the inter-AS seamless MPLS networking with a core-layer BGP LSP established. Seamless MPLS is mainly used to transmit VPN packets. The following example demonstrates how VPN packets, including labels and data, are transmitted from a CSG to an MASG along the path CSG1 -> AGG1 -> AGG ASBR1 -> core ASBR1 -> MASG1.

1. The CSG pushes a BGP LSP label and an MPLS tunnel label in sequence into each VPN packet and forwards the packets to the AGG.
2. The AGG removes the access-layer MPLS tunnel labels from the packets and swaps the existing BGP LSP labels for new labels. The AGG pushes an aggregation-layer MPLS tunnel label into each packet and then proceeds to forward the packets to the AGG ASBR. If the PHP function is enabled on the AGG, the CSG has removed the MPLS tunnel labels from the packets, and therefore, the AGG receives packets without MPLS tunnel labels.
3. The AGG ASBR then removes the MPLS tunnel labels from packets and swaps the existing BGP LSP label for a new label in each packet. It then forwards the packets to the core ASBR. If the PHP function is enabled on the AGG ASBR, the AGG has removed the MPLS tunnel labels from the packets, and therefore, the AGG ASBR receives packets without MPLS tunnel labels.
4. After the core ASBR receives the packets, it swaps a BGP LSP label for a new label and adds a core-layer MPLS tunnel label to each packet. It then forwards the packets to the MASG.
5. The MASG removes MPLS tunnel labels, BGP LSP labels, and VPN labels from the packets. If the PHP function is enabled on the MASG, the core ASBR has removed the MPLS tunnel labels from the packets, and therefore, the MASG receives packets without MPLS tunnel labels.
   The VPN packet transmission along the inter-AS seamless MPLS tunnel is complete.

Figure 4 Forwarding plane for the inter-AS seamless MPLS networking without a BGP LSP established in the core area 

Figure 4 illustrates the forwarding plane for the inter-AS seamless MPLS networking without a BGP LSP established in the core area. The process of transmitting packets on this network is similar to that on a network with a BGP LSP established. The difference is that without a BGP LSP in the core area, the core ASBR removes BGP labels from packets and add MPLS tunnel labels to these packets.

Basic Principles of Seamless MPLS - Part 1

Usage Scenario

Seamless MPLS establishes a BGP LSP across the access, aggregation, and core layers and transmits services along the E2E BGP LSP. Service traffic can be transmitted between any two points on the LSP. The seamless MPLS network architecture maximizes service scalability using the following functions:

• Allows access nodes to signal all services to an LSP.
• Uses the same transport layer convergence technique to rectify all network-side faults, without affecting service transmission.

Seamless MPLS networking solutions are as follows:

• Intra-AS seamless MPLS: The access, aggregation, and core layers are within a single AS. Intra-AS seamless MPLS applies to mobile bearer networks.
• Inter-AS seamless MPLS: The access and aggregation layers are within a single AS, whereas the core layer in another AS. Inter-AS seamless MPLS is mainly used to transmit enterprise services.
• Inter-AS seamless MPLS+HVPN: A cell site gateway (CSG) and an aggregation (AGG) node establish an HVPN connection, and the AGG and a mobile aggregate service gateway (MASG) establish a seamless MPLS LSP. The AGG provides hierarchical L3VPN access services and routing management services. Seamless MPLS+HVPN combines the advantages of both MPLS and HVPN. Seamless MPLS allows any two nodes on an inter-AS LSP to transmit services at the access, aggregation, and core layers, providing high service scalability. HVPN enables carriers to reduce network deployment costs by deploying devices with layer-specific capacities to meet service requirements.

Intra-AS Seamless MPLS:

Network Deployment :

Control plane

- Deploy routing protocols 

Figure 1 Deploying routing protocols for the intra-AS seamless MPLS networking

As shown in Figure 1, routing protocols are deployed on devices as follows:

• An IGP (IS-IS or OSPF) is enabled on devices at each of the access, aggregation, and core layers to implement intra-AS connectivity.
• The path CSG1 -> AGG1 -> core ABR1 -> MASG1 is used in the following example. An IBGP peer relationship is established between each of the following pairs of devices:
  

  • CSG and AGG
  • AGG and core ABR
  • Core ABR and MASG
  The AGG and core ABR are configured as route reflectors (RRs) so that the CSG and MASG can obtain routes destined for each other's loopback addresses.
• The AGG and core ABR set the next hop addresses in BGP routes to their own addresses to prevent advertising unnecessary IGP area-specific public routes.

- Deploy tunnels

Figure 2 Deploying tunnels for the intra-AS seamless MPLS networking

As shown in Figure 2, tunnels are deployed as follows:

• A public network tunnel is established using LDP or TE in each IGP area.
• The path CSG1 -> AGG1 -> core ABR1 -> MASG1 is used in the following example. An IBGP peer relationship is established between each of the following pairs of devices:
  

  • CSG and AGG
  • AGG and core ABR
  • Core ABR and MASG
  These devices are enabled to advertise labeled routes and assign labels to BGP routes that match a specified routing policy. After the devices exchange labeled BGP routes, an E2E BGP LSP is established between the CSG and MASG.

Forwarding plane

Figure 3 Forwarding plane for the intra-AS seamless MPLS networking

Figure 3 illustrates the forwarding plane of the intra-AS seamless MPLS networking. Seamless MPLS is mainly used to transmit VPN packets. The following example demonstrates how VPN packets, including labels and data, are transmitted from a CSG to an MASG along the path CSG1 -> AGG1 -> core ABR1 -> MASG1.

1. The CSG pushes a BGP LSP label and an MPLS tunnel label in sequence into each VPN packet and forwards the packets to the AGG.
2. The AGG removes the access-layer MPLS tunnel labels from the packets and swaps the existing BGP LSP labels for new labels. The AGG then pushes an aggregation-layer MPLS tunnel label into each packet. The AGG proceeds to forward the packets to the core ABR. If the penultimate hop popping (PHP) function is enabled on the AGG, the CSG has removed the MPLS tunnel labels from the packets, and therefore, the AGG receives packets without MPLS tunnel labels.
3. The core ABR removes aggregation-layer MPLS tunnel labels from the VPN packets and swaps the existing BGP LSP labels for new labels. The AGG pushes a core-layer MPLS tunnel label to each packet and forwards the packets to the MASG.
4. The MASG removes MPLS tunnel labels and BGP LSP labels from the VPN packets. If the PHP function is enabled on the MASG, the core ABR has removed the core-layer MPLS tunnel labels from the packets, and therefore, the MASG receives packets without MPLS tunnel labels.
   The VPN packet transmission along the intra-AS seamless MPLS tunnel is complete.

ATM Services over IPRAN

Here is how the TDM services working over IPRAN :

TDM Services over IPRAN

here is how the TDM services working over IPRAN :

How the services work in IPRAN ?

Hi my friends ,
Today I found a very good Video that explain how the services are working on IPRAN
this will help you soo much to understand how the traffic is moving inside the network and how its encapsulated
Here you will see how the encapsulation if the access node is Ethernet :

How the Network works ?

Hi guys

I want to share with you today a very useful video on how the Network and the packets inside the network moved from your computer the the internet