Simple client-server notifications system

I need to develop a notifications system over the internet in which clients can send notifications that will be delivered and displayed promptly to the other clients. 1. Client 1.1. Notify 1.1.1. There is text box in which the user enters his message. 1.1.2. The User hits the "Notify" Button 1.1.3. The notification is sent to the server 1.1.4.1 The Server store the notification in its database 1.1.4. 2 The server sends the notification to a specific client or broadcasting it to all the registered clients. 1.1.5. Client that receive a notification from the server, displays it immediately (Sender name + message) in a status line. 1.1.6. Low latency is appreciated (no more than 1 sec for the full round-trip on the internet) 1.2 Register 1.2.1 There is a "Register" Button (in the client GUI - that inform the server to send him the notifications. 1.3.1 A Full solution includes both: 1.3.1.1 Desktop Winform Application client 1.3.1.2 Web client. 1.4 You may assume the clients are typicel home users: 1.4.1 Is there any firewall considerations 1.4.2 try avoid manual configuratin when installing the client 2. Server 2.1 Should have a simple GUI for tracing its activity. 3. Non-functional Requirements 3.1 Both Client and server will be implemented in C# - In case Other than C# will be used please specify it in your bid. 3.2 The solution should include full ready to compile source code and guidelines on how to install/configure the server 4. When Bidding 4.1 Please specify in few lines about the proposed Architecture/Technology you are going to use for implementation. 4.2 Are there any required resources for deployment (e.g. hosting, etc...) 4.3 Feel free to ask any question needed for clarification. Thanks Moran