ABC Cоmmunicаtiоns, а Tier 2 ISP, wаnts tо provide Internet access to its customers. The ISP is considering two options: establishing peering agreements with neighboring Tier 2 ISPs or purchasing transit service from a Tier 1 ISP. ABC finds peering to be more cost-effective and enters into several peering arrangements. Despite these, why might ABC Communications still need to purchase transit from a Tier 1 ISP?