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Using Smart SFPs for Transporting Legacy Network Traffic over Packet Switched Networks

This topic describes how to transport legacy TDM traffic over Packet switched networks using Smart SFP transceivers.

Transporting Legacy Traffic over Packet Switched Networks

Legacy networks such as SONET and SDH, which are used for very high-speed transmission of voice and data signals across the numerous fiber-optic networks, still operate worldwide. These legacy networks use time-division multiplexing (TDM), which ensures that a constant stream of data travels on the network. Lower bit-rate streams of information are combined, or multiplexed, up into higher bit-rate streams to take advantage of the bandwidth available. Today, as data is the most significant type of traffic on the legacy networks, most organizations are planning to migrate their existing legacy networks to packet-switched networks (PSNs), which are better suited for data transport. However, a part of the network traffic continues to remain TDM-based. And migrations are expensive and require detailed planning for allocation of rack space, power, and new equipment.

To ensure seamless migration from legacy networks to PSNs in a cost-effective and space-optimized manner, you can use smart small form-factor pluggable (SFP) transceivers. Install a smart SFP transceiver on your router or switch and easily transport TDM traffic (converted into a packet stream) across a PSN.

TDM traffic is broadly classified into: Plesiochronous Digital Hierarchy (PDH) and Synchronous Digital Hierarchy (SDH) traffic. Both PDH and SDH technologies are associated with digital multiplexers. In PDH traffic, the bit streams are of same bit rate but are derived from different clocks that belong to different oscillators. Hence, the name Plesiochronous. Examples of PDH interfaces are E1, T1, and DS3. In SDH traffic, the bit streams are of the same bit rate but are derived from a common clock and are thus synchronous. Examples of SDH interfaces are STM1, STM4, and STM16. Based on the type of legacy TDM traffic, PDH or SDH, you can choose Smart SFP optics to convert the legacy packets to Ethernet frames that can be transported over PSNs.

Smart SFP Transceivers for Transporting PDH Traffic over PSNs Overview

Junos OS supports the following three smart SFP transceivers on MX Series routers for transporting PDH traffic over PSNs:

  • DS3 smart SFP (SFP-GE-TDM-DS3)

  • E1 smart SFP (SFP-GE-TDM-E1)

  • T1 smart SFP (SFP-GE-TDM-T1)

On your MX Series router, the MPC1, MPC2, MPC3 line cards, the Gigabit Ethernet MIC with SFP (MIC-3D-20GE-SFP), Gigabit Ethernet MIC with SFP (E) (MIC-3D-20GE-SFP-E), Gigabit Ethernet MIC with SFP (EH) (MIC-3D-20GE-SFP-EH), and the Gigabit Ethernet MIC with 256b-AES MACSEC (MIC-MACSEC-20GE) modular interface cards support the smart SFP transceivers.

The smart SFP transceivers encapsulate traffic on PDH interfaces on the WAN side as Ethernet frames on the system side. The encapsulated traffic from the transceivers is sent over the PSNs provisioned across the network. You can further encapsulate the PDH interfaces using MEF8 or MPLS framing. You can also configure single or dual VLAN tagging within a default emulation circuit identifier (ECID).

You can encapsulate E1 and T1 traffic as Ethernet frames by using Structure Agnostic TDM over Packet (SAToP) using MEF8 framing. MPLS framing and both single and dual VLAN tagging are supported. E1 and T1 encapsulation uses the SAToP according to Transparent PDH over Packet (TPoP) standard. You can encapsulate DS3 traffic as Ethernet frames using MEF8 or MPLS framing. Both single and dual VLAN tagging is supported. DS3 encapsulation uses the Virtual Container over Packet (VCoP) standard.

At the local end, the smart SFP transceiver slices the TDM data stream, encapsulates the Ethernet frames and pushes it onto the PSN. The smart SFPs are always paired on the other end of the emulated circuit, and are preconfigured to be in the same multicast MAC address group. At the far end, the smart SFP transceiver decapsulates the Ethernet frames, re-builds the TDM data stream, and forwards it onto the local TDM interface.

Smart SFP Transceivers for Transporting SDH Traffic over PSNs Overview

Junos OS supports the following three smart SFP transceivers on MX Series routers for transporting SDH traffic over PSNs:

  • STM1 smart SFP (SFP-GE-TDM-STM1)

  • STM4 smart SFP (SFP-GE-TDM-STM4)

  • STM16 smart SFP (SFP-GE-TDM-STM16)

On your MX Series router, the MPC1, MPC2, MPC3 line cards, the Gigabit Ethernet MIC with SFP (MIC-3D-20GE-SFP), Gigabit Ethernet MIC with SFP (E) (MIC-3D-20GE-SFP-E), Gigabit Ethernet MIC with SFP (EH) (MIC-3D-20GE-SFP-EH), and the Gigabit Ethernet MIC with 256b-AES MACSEC (MIC-MACSEC-20GE) modular interface cards support the smart SFP transceivers. Only the 10-Gigabit Ethernet interfaces on the 256-AES MACSEC MIC support the STM16 smart SFP (SFP-GE-TDM-STM16).

Note:

The MPC4E (MPC4E-3D-32XGE-SFPP and MPC4E-3D-2CGE-8XGE) line card supports the STM16 smart SFP transceiver.

The smart SFP transceivers encapsulate traffic on SDH interfaces on the WAN side as Ethernet frames on the system side. The encapsulated traffic from the SFP transceivers is sent over the PSNs provisioned across the network. You can encapsulate the SDH interfaces using MEF8 framing. You can also configure single VLAN tagging within a default emulation circuit identifier (ECID).

You can encapsulate STM traffic as Ethernet frames using MEF8 framing. Only single VLAN tagging is supported. STM encapsulation uses the Transparent SONET/SDH over Packet (TSoP) standard.

At the local end, the smart SFP transceiver slices the TDM data stream, encapsulates the Ethernet frames and pushes it onto the PSN. The smart SFPs are always paired on the other end of the emulated circuit, and are preconfigured to be in the same multicast MAC address group. At the far end, the smart SFP transceiver decapsulates the Ethernet frames, re-builds the TDM data stream and forwards it onto the local TDM interface.

Benefits of Smart SFP Transceivers

  • Lower operational costs—Smart SFP transceivers enable easy and simplified migration and upgrades from legacy networks to PSNs.

  • Operational simplicity and flexibility—You don’t need to configure individual TDM interfaces over packet connections. You can deploy additional equipment only if you need it.

  • Space saving. Does not require additional rack space.

  • Low carbon footprint. Lower power consumption and existing equipment such as TDM access nodes are still in use after migration. Reduced electronic waste.

  • Definitive migration to only-Ethernet based network equipment, removing the need to have dedicated TDM network interface cards for the termination of the TDM lines.

Example: Configuring the Smart-SFPs on MX Series Routers for transporting legacy PDH Traffic

Requirements for Configuration of the Smart-SFPs on MX Series Routers

This example uses the following hardware and software components:

  • Junos OS Release 19.4R1 or later for MX Series routers

  • A single MX480 router

  • DS3 Smart SFP (SFP-GE-TDM-DS3) transceiver

Overview

This example provides information about configuring the DS3 Smart SFP (SFP-GE-TDM-DS3) transceiver on an MX480 router to enable the transceiver to encapsulate DS3 packets as Ethernet frames while transporting the packets from legacy networks to PSNs. You can configure the DS3 Smart SFP to further encapsulate the DS3 packets using MEF8 or MPLS framing as VCoP (Virtual container over Packet) for DS3 interfaces. You can also configure single or dual VLAN tagging.

The TDM data stream, sliced, and encapsulated into Ethernet frames is pushed into the PSN to reach the far end point of a similar SFP type. The Smart SFPs are always paired on the other end of the emulated circuit and are pre-configured to be part of the same multicast MAC address group. At the far end, the smart SFP transceiver decapsulates the Ethernet frames, re-builds the TDM data stream and forwards it onto the local TDM interface.

Configuring the DS3 Smart SFP

Procedure

Step-by-Step Procedure

In this example, you configure the Smart SFP to transport PDH traffic over PSN networks. To configure the Smart SFP, perform the following tasks:

  1. In Configuration mode, create a valid Interface to enable the Smart SFP to communicate with the Junos OS. Configuring VLAN tagging creates a control interface.

  2. Specify the type of Smart SFP to be configured on the interface. In this example, we are configuring a DS3 Smart SFP.

  3. (Optional) Configure the destination MAC address on the local end smart SFP using the dmac-address statement at the [edit interfaces ge-4/0/0 tdm-options] hierarchy level to encapsulate the MAC address of the far end smart SFP. To enable MAC address validation or checking of the destination MAC address at the far end smart SFP, use the ces-psn-port-dmac-check-enable statement. If the MAC address of the packet does not match, the packet is discarded.

  4. (Optional) Configure the encapsulation mode (MEF8 or MPLS) for further network processing. The default encapsulation mode for DS3 Smart SFP is MEF8.

  5. (Optional) Configure single or dual VLAN tagging on the encapsulated packets. DS3 Smart SFP supports both single and dual VLAN tagging. If you want to configure single VLAN tagging, use the vlan-id-1 statement and specify the VLAN ID. If you want to configure dual VLAN tagging, use vlan-id-1 and vlan-id-2 statements to configure the inner and outer VLAN IDs. Possible values for the VLAN ID: 0 through 4094.

  6. (Optional) Configure the emulation circuit ID for encapsulation and decapsulation. If you do not specify an emulation circuit ID, the default value is 0. Possible values for the encapsulation and decapsulation ID: 0 through 1048575.

  7. (Optional) Specify if you require checking of the destination MAC address of the incoming packets on the receiving SFP at the [edit interfaces ge-4/0/0 tdm-options] hierarchy. If you have configured the destination MAC address using the dmac-address option, use this option to verify the MAC address on the receiving SFP. If you have enabled MAC address verification and the MAC address does not match, the packet is discarded by the smart SFP.

  8. (Optional) Enable looping back of the input path of TDM traffic on the SFP TDM port. The input path refers to the traffic from the TDM side that is looped back.

  9. (Optional) Enable looping back of the output path of TDM traffic on the SFP TDM port. The output path refers to the traffic from the Ethernet side that is looped back.

Verification

To verify that the DS3 Smart SFP is configured on the MX480 router, perform the following tasks:

Verifying the DS3 Smart SFP Statistics on the Interface

Purpose

To verify that the DS3 Smart SFP is configured on the MX480 router and to view the DS3 Smart SFP statistics.

Action

To view the DS3 Smart SFP statistics on the Interface, use the show interfaces ge-4/0/0 smart-sfp-statistics command.

Meaning

The DS3 Smart SFP is configured on the MX480 router and you can view the DS3 Smart SFP statistics.

Example: Configuring the Smart-SFPs on MX Series Routers for transporting legacy SDH Traffic

Requirements for Configuration of the Smart-SFPs on MX Series Routers

This example uses the following hardware and software components:

  • Junos OS Release 19.4R1 or later for MX Series routers

  • A single MX480 router

  • STM1 Smart SFP (SFP-GE-TDM-STM1) transceiver

Overview

This example provides information about configuring the STM1 Smart SFP (SFP-GE-TDM-STM1) transceiver on an MX480 router to enable the transceiver to encapsulate STM1 packets as Ethernet frames while transporting the packets from legacy networks to PSNs. You can configure the STM1 Smart SFP to further encapsulate the STM1 packets using MEF8 framing as TSoP (Transparent SONET/SDH over Packet) for STM1 interfaces. You can only configure single VLAN tagging.

The TDM data stream, sliced, and encapsulated into Ethernet frames is pushed into the PSN to reach the far end point of a similar SFP type. The Smart SFPs are always paired on the other end of the emulated circuit and are pre-configured to be part of the same multicast MAC address group. At the far end, the smart SFP transceiver decapsulates the Ethernet frames, re-builds the TDM data stream and forwards it onto the local TDM interface.

Configuring the STM1 Smart SFP

Procedure

Step-by-Step Procedure

In this example, you configure the Smart SFP to transport SDH packets over PSNs. To configure the Smart SFP, perform the following tasks:

  1. In Configuration mode, create a valid Interface to enable the Smart SFP to communicate with the Junos OS. Configuring VLAN tagging creates a control interface.

  2. Specify the type of Smart SFP to be configured on the interface. In this example, we are configuring a STM1 Smart SFP.

  3. (Optional) Configure the destination MAC address using the dmac-address statement at the [edit interfaces ge-3/0/0 tdm-options] hierarchy level to encapsulate the MAC address of the far end smart SFP. To enable MAC address validation or checking of the destination MAC address at the far end smart SFP, use the ces-psn-port-dmac-check-enable statement. If the MAC address of the packet does not match, the packet is discarded.

  4. (Optional) Configure the encapsulation mode (MEF8 only) for further network processing. The default encapsulation mode for STM1 Smart SFP is MEF8.

  5. (Optional) Configure single VLAN tagging on the encapsulated packets. STM1 Smart SFP supports only single VLAN tagging. If you want to configure single VLAN tagging, use the vlan-id-1 statement and specify the VLAN ID. Possible values for the VLAN ID: 0 through 4094.

  6. (Optional) Configure the emulation circuit ID for encapsulation and decapsulation. If you do not specify an emulation circuit ID, the default value is 0. Possible values for the encapsulation and decapsulation ID: 0 through 1048575.

  7. (Optional) Specify if you require checking of the destination MAC address of the incoming packets on the receiving SFP at the [edit interfaces ge-3/0/0 tdm-options] hierarchy. If you have configured the destination MAC address using the dmac-address option, use this option to verify the MAC address on the receiving SFP. If you have enabled MAC address verification and the MAC address does not match, the packet is discarded by the smart SFP.

  8. (Optional) Enable looping back of the input path of TDM traffic on the SFP TDM port. The input path refers to the traffic from the TDM side that is looped back.

  9. (Optional) Enable looping back of the output path of TDM traffic on the SFP TDM port. The output path refers to the traffic from the Ethernet side that is looped back.

Verification

To verify that the STM1 Smart SFP is configured on the MX480 router, perform the following tasks:

Verifying the STM1 Smart SFP Statistics on the Interface

Purpose

To verify that the STM1 Smart SFP is configured on the MX480 router and to view the STM1 Smart SFP statistics.

Action

To view the STM1 Smart SFP statistics on the Interface, use the show interfaces ge-3/0/0 smart-sfp-statistics command.

Meaning

The STM1 Smart SFP is configured on the MX480 router and you can view the STM1 Smart SFP statistics.