> For the complete documentation index, see [llms.txt](https://prosbcdocs.telcobridges.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://prosbcdocs.telcobridges.com/initial-installation/1.-instructions-by-platform/network-interface-requirements.md).

# Network Interface Requirements

This page describes how many network interfaces (NICs) a ProSBC deployment needs for each topology, and how to wire the control interfaces when ProSBC is deployed as a High Availability (1+1) system.

{% hint style="info" %}
**NIC** = Ethernet network interface. Interfaces marked with an asterisk (\*) must use an approved NIC card (for example, Intel I350-T4). See [List of Supported Network Interface Cards](/initial-installation/1.-instructions-by-platform/baremetal-installation/list-of-supported-network-interface-cards.md).
{% endhint %}

#### Interfaces required per deployment topology

| Deployment topology               | Management | VoIP\*                            | Transcoder RTP\* | Control ports (ctrl0/ctrl1) |
| --------------------------------- | ---------- | --------------------------------- | ---------------- | --------------------------- |
| Standalone                        | 1 NIC      | 1 NIC (or 2 to separate networks) | —                | —                           |
| Standalone with transcoder device | 1 NIC      | 1 NIC (or 2)                      | 2 NICs           | 2 NICs                      |
| 1+1 (per unit)                    | 1 NIC      | 1 NIC (or 2)                      | —                | 2 NICs                      |
| 1+1 with transcoder (per unit)    | 1 NIC      | 1 NIC (or 2)                      | 2 NICs           | 2 NICs                      |

Use two NICs for VoIP when you want to separate networks (for example, an access-side and a core-side network).

#### Connecting the control interfaces in a 1+1 system

When using ProSBC in a 1+1 architecture, you need two interfaces for redundancy, called **ctrl0** and **ctrl1**.

* **Without a transcoding device** — ctrl0 and ctrl1 can be connected **directly** between the two servers (or virtual machines).
* **With a transcoding device** — ctrl0 and ctrl1 **cannot** be connected directly, because these interfaces are also used to control the transcoding devices. They must be on a **private network** between the ProSBC controllers and the transcoding devices. On the transcoding device, these interfaces are named **eth0/eth1** (instead of ctrl0/ctrl1).

#### Related

* [List of Supported Network Interface Cards](/initial-installation/1.-instructions-by-platform/baremetal-installation/list-of-supported-network-interface-cards.md)
* [ProSBC Requirements Matrix](/initial-installation/1.-instructions-by-platform/prosbc-requirements-matrix.md)
* [Setting the Role to a Primary Unit in a 1+1 System](/configuration-details/configuration-by-web-portal-category/system-settings/setting-the-role-to-a-primary-unit-in-a-1+1-system.md)
* [Setting the Role to a Secondary Unit in a 1+1 System](/configuration-details/configuration-by-web-portal-category/system-settings/setting-the-role-to-a-secondary-unit-in-a-1+1-system.md)
* [Transcoding Unit Configuration](/configuration-details/configuration-by-use-case/transcoding-unit-configuration.md)


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