Site to Site Connectivity

Hi All,

One of my client is wants to refresh the existing solution for site to site connectivity. They are aiming to reduce WAN costs and looking at what options are available for them. All together there are 5 sites, approximately a 100 users at remote site and 200 at the head office.

I am new to the networking Arena and wondering if someone can help me with this or point me in a right direction.

Any help is much appreciated and i thank you in advance.

I look forward to your replies.

Thanks