Datacom
08/02/2020
MPLS Datacom interoperability with other manufacturers

By Guilherme Pfeiff - Network Applications Engineer

The network, known today as the Internet, is made up of millions of interconnected equipment from the most varied manufacturers. In order for them to interoperate, international standards must be followed. The standards defined by the IEEE, ITU-T and IETF bodies aim to guide manufacturers on how each relevant network protocol should be developed and implemented.

Even though these standards exist, there are several non-mandatory parts in the development of the standard that the manufacturer can choose to insert its standard or its default configuration. These implementation details can generate an incompatibility or need to change the factory configuration for the equipment to communicate. An example that we can cite (and that we will see in more detail later in the article) in this question of difference in default configuration is the size of the MTU (Maximum Transmission Unit) of a circuit delivered through an L2VPN MPLS between Datacom and Huawei *:

In the Datacom equipment, we used the size of 9,198 Bytes in the initial configuration, while the equipment of the manufacturer Huawei *, such as S6720 for example, uses the size of 1,500 Bytes as standard. This small configuration detail makes the VPN not up, and as a consequence, there is no delivery of customer traffic.

This small example shows us that in addition to reliability, ease of configuration, technical support and price, both large operators and small Internet service providers must also evaluate the interoperability issue when designing their networks.

Aware of this concern, Datacom has a system of systemic tests that validate compatibility with equipment from the main world manufacturers. With each new firmware version, these tests are automatically re-performed to ensure that there was no compatibility break.

 

1.1 What will we see in this article?

 

To demonstrate the compatibility of MPLS Datacom and Huawei *, a simple scenario with a linear topology involving 1x DM4370 (EDD 10G Datacom) and 2x Huawei S6720 * was set up. In this topology we create an OSPF and L2VPNs infrastructure of the VPWS and VPLS types.

During the article you will see all the parameters necessary for VPNs to rise, however it is important to note that most of the incompatibility problems in this scenario are related to the MTU configuration of L2VPNs.

If you want to check how to change the MTU sizes on the Datacom equipment interfaces, you can skip to the end of the article (Chapter 5. MTU).

 

 

2 Basic Infrastructure Configurations

 

2.1 OSPFv2

 

OSPFv2 was the IGP (Internal Gateway Protocol) used to route addresses and serve as part of the infrastructure of our scenario.

The topology below will be used to demonstrate the configuration of OSPFv2.

 

Figure 1. Scenario - OSPFv2 protocol

 

This topology presents the OSPF configuration in area 0 with a point-to-point network-type through the following parameters:

- DM4370: L3 interface on VLAN 10 with IPv4 address 200.0.0.1/30 and loopback interface with IPv4 200.200.200.3/32 being used as router-id in OSPFv2 in area 0.

- Huawei S6720-1 *: L3 interface on VLAN 10 with IPv4 address 200.0.0.2/30, VLAN 20 with IPv4 address 200.0.0.5/30 and loopback interface with IPv4 200.200.200.1/32 being used as router-id in OSPFv2 on area 0.

- Huawei S6720-2 *: L3 interface on VLAN 20 with IPv4 address 200.0.0.6/30 and loopback interface with IPv4 200.200.200.2/32 being used as router-id in OSPFv2 in area 0.

 

 

Below are the main commands available to perform the OSPFv2 verification.

 

 

2.2 LDP - Label Distribution Protocol

 

LDP requires the configuration of a routing protocol. OSPF, shown in the previous item, was used as a basis.

The topology below will be used to demonstrate the configuration of the MPLS infrastructure using LDP.

 

Figure 2. Example scenario with the LDP infrastructure

 

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Below are the main commands available to perform the LDP check.

 

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3 MPLS L2VPN VPWS

 

In this item, some scenarios and interoperability configurations of VPWS and VPLS between Datacom DmOS equipment with Huawei * will be demonstrated.

 

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The scenario below will be used to demonstrate the configurations of VPWS L2VPNs between the DM4370 and the Huawei S6720-2.

 

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Figura 3. Exemplo de cenário com L2VPN VPWS

 

3.1 L2VPN VPWS with pw-type VLAN

 

When selecting the pw-type as VLAN, all VPN traffic will be transported with service-delimiting or service VLAN tags.

Below are 2 examples of VPWS configurations: pw-type vlan + vlan based; pw-type vlan port based.

 

3.1.1 VPWS VLAN Based with pw-type VLAN

 

This configuration mode allows the connection of several clients on the same access interface, as the VPN encapsulation is done when the packet received on the access port is matched in the vlan. In DmOS this is done through the “access-interface” + “dot1q” config as shown in the example below.

 

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Below are the main commands available to verify L2VPNs VPWS.

 

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3.1.2 VPWS Port Based with pw-type VLAN

 

In port based VPN, all traffic received on the PE access interface will be encapsulated, whether with or without VLAN dialing. The exception to this rule occurs if there are other VPNs of the VLAN Based type configured on this same access port. In this case, VLANs that match VPNs will be encapsulated by their respective VPNs, while all traffic that does not match VLANs will be encapsulated by the Port Based VPN. This configuration is done through the use of "VLAN Delimiting" as shown below.

 

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Below are the main commands available to verify L2VPNs VPWS.

 

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3.2 L2VPN VPWS WITH PW-TYPE ETHERNET

 

When selecting the pw-type as Ethernet, all VPN traffic will be carried without a service VLAN tag or service-delimiting.

Below are 2 examples of VPWS configurations: pw-type vlan + vlan based; pw-type vlan port based.

 

3.2.1 VPWS Port Based with pw-type Ethernet

 

In port based VPN, all traffic received on the PE access interface will be encapsulated, whether with or without VLAN dialing. The exception to this rule occurs if there are other VPNs of the VLAN Based type configured on this same access port. In this case, VLANs that match VPNs will be encapsulated by their respective VPNs, while all traffic that does not match VLANs will be encapsulated by the Port Based VPN.

 

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Below are the main commands available to verify L2VPNs VPWS.

 

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4 MPLS L2VPN VPLS

 

The scenario below will be used to demonstrate the configurations of VPLS L2VPNs between the DM4370 and the Huawei S6720-2 *.

 

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Figura 4. Exemplo de cenário com L2VPN VPLS

 

4.1 L2VPN VPLS WITH PW-TYPE VLAN

 

When selecting the pw-type as VLAN, all VPN traffic will be transported with service-delimiting or service VLAN tags.
Below are 2 examples of VPLS configurations: pw-type vlan + vlan based; pw-type vlan port based.

 

4.1.1 VPLS VLAN Based with pw-type VLAN

 

This configuration mode allows the connection of several clients on the same access interface, since the VPN encapsulation is performed when the packets received on the access port match the VLAN. In DmOS this is done through the “access-interface” + “dot1q” config as shown in the example below.

 

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Below are the main commands available to carry out the verification of L2VPNs VPLS.

 

 

4.1.2 VPLS Port Based with pw-type VLAN

 

This configuration mode allows the connection of several clients on the same access interface, since the VPN encapsulation is performed when the packets received on the access port match the VLAN. In DmOS this is done through the “access-interface” + “dot1q” config as shown in the example below.

 

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Below are the main commands available to carry out the verification of L2VPNs VPLS.

 

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4.2 L2VPN VPLS WITH PW-TYPE ETHERNET

 

When selecting the pw-type as Ethernet, all VPN traffic will be carried without a service VLAN tag or service-delimiting.

 

4.2.1 VPLS Port Based with pw-type Ethernet

 

In port based VPN, all traffic received on the PE access interface will be encapsulated, whether with or without VLAN dialing. The exception to this rule occurs if there are other VPNs of the VLAN Based type configured on this same access port. In this case, VLANs that match VPNs will be encapsulated by their respective VPNs, while all traffic that does not match VLANs will be encapsulated by the Port Based VPN.

 

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Below are the main commands available to carry out the verification of L2VPNs VPLS.

 

 

5 MTU

 

The default MTU configuration for Huawei * is different from Datacom devices. In Huawei S6720 * the MTU of the ethernet interface is 9216 Bytes, the VLAN (Vlanif) interface 1500 Bytes and the L2VPN 1500 Bytes. In Datacom equipment, the MTU of the ethernet interfaces follows the maximum supported by the hardware of each model, in the case of the DM4370 it is 12266 Bytes. On the VLAN interface (L3 interface) 1500 Bytes and L2VPN 9190 Bytes.

Observing these parameter differences, it is necessary to change the MTU configuration of the L2VPN in one of the two devices. In the example of the article, the configuration of Huawei * equipment was changed.

 

Commands for changing MTU in Datacom:

 

- Changing the MTU of an interface:

 

- Changing the MTU of a VPN:

 

- Changing the MTU of an L3 Interface:

 

These were the necessary steps to set up L2VPNs between Datacom and Huawei. It is important to highlight that Datacom has a complete structure in its headquarters where on-site training is offered. With Datacom's MPLS technology training, you will be able to explore various topics in more depth.

In the training it will be possible to manipulate the equipment, perform configurations of different topologies and application scenarios in a complete laboratory environment, in addition to being able to count on the help of our professionals in a series of good practices that will greatly assist in the operation of your network.

For questions and request for proposal, do not hesitate to contact Datacom's commercial team: sales@datacom.com.br or phone (+55) 51 3933 3000.

 

* All third-party product and company names are trademarks or registered trademarks of their respective owners, with no affiliation or endorsement by them being mentioned in this document.

 

 

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