---
title: "Screen Sharing Across Guest Wi-Fi & VLANs | Mersive"
canonical: https://www.mersive.com/platform/cross-network
description: "Cross-network screen sharing without VPN: guests, VLANs and remote devices connect over direct encrypted WebRTC with outbound-only TLS signaling on port 443."
language: en-US
publisher: Mersive Technologies
---

# Screen sharing across guest Wi-Fi, VLANs, and segmented networks.

Subnets, VLANs, guest Wi-Fi, LTE, the building across town: one workspace, no VPN, no UC call, no cables. This is the capability that sets Polaris apart.

Every session here crosses a network

Guest on LTE in London shares to a Denver boardroom. Both ends dial out; media goes direct.

signaling — outbound TLS 443, both ends dial out media — direct between the two endpoints relayed media — the fallback, one extra hop a NAT no direct path can cross

**1.** A guest on LTE tries to reach the display directly. No route exists, and none will be created. **2.** The share leaves their browser instead: outbound TLS signaling on TCP 443 to webrtc.mersive.com. **3.** The cloud introduces the two endpoints; they negotiate a direct, encrypted WebRTC connection. Nothing routes through Mersive; nothing bridges. **4.** Content flows device-to-display over that direct connection. Signaling is outbound-only on both sides: no inbound firewall rules.

thin dashes: signaling to the cloud, outbound TLSbold lines: media, direct between endpointsguest shares from the browser, no apphatched walls: routes that never exist; openings: negotiated flows only

The fallback, in full

## When no direct path can be formed, the media takes one relayed hop.

The globe above ends one session in four this way. This is that hop, message by message — what the relay is asked for, what it is allowed to forward, and what it can see.

A symmetric NAT gives every destination a different external port, so the address the display was handed is not the address packets would arrive from.

the device and its NATrelay control messages, then relayed mediaencryption the relay is outside ofhatched walls: the NAT and the firewall, neither of which is opened

Where this saves the day

## Three rooms that break a LAN-local system.

### The guest presenter

A board member walks in on LTE. No guest Wi-Fi sign-up, no VPN token, no dongle. They join the workspace from a browser and present in under a minute, with zero access to your network.

[Try it in your boardroom →](https://www.mersive.com/trial)

### The segmented enterprise

Corp, guest, AV, and OT networks that must never route to each other, by policy. Polaris keeps the isolation intact and still lands every source on the same display.

[The enterprise story →](https://www.mersive.com/solutions/enterprise)

### The multi-building campus

Engineering in Building C shares to the war room in Building A, across VLANs and fiber, without spinning up a UC call just to move pixels.

[Campus scale →](https://www.mersive.com/solutions/highered)

How cross-network signaling works

### Where your content actually goes

Polaris Cloud introduces the two ends of a share. It does not carry them.

When a source and a display sit on different networks, the signaling service at webrtc.mersive.com exchanges connection details between the sharing device and the display, and the two negotiate a direct, encrypted WebRTC connection between themselves. Your content travels from the device to the display. It does not pass through Mersive.

- **What reaches our cloud:** session signaling, the connection details the two endpoints need to find each other. Not your screen.
- **What stays on your network:** when a source and a display are already on the same network, the connection is negotiated with local addresses only and never leaves the LAN.
- **What never happens:** no inbound firewall rules, no bridging of your networks. All cloud traffic is outbound TLS on TCP 443 from both sides. A guest device gets zero access to your network; the workspace is the only shared surface.

The short version

## The combination of cross-network capability without a VPN, the workspace, and meeting parity with a composited workspace available in a web browser sets Polaris apart.

✓ No VPN✓ No UC call✓ No inbound holes✓ Guest gets zero network access✓ Every Polaris tier

[Check the matrix →](https://www.mersive.com/compare/hub) [The security read →](https://www.mersive.com/security)