MANET (Mobile Ad-hoc Network) could also be a self-configuring and infrastructure less network that consists of mobile nodes that communicate with each other through wireless links. This paper analyzes the Blackhole attack which is one of the possible attacks in ad-hoc networks. The intruder, once chosen as an intermediate node, drops the packets instead of forwarding or processing them, causing a neighborhood (BH) within the network. The goal is to develop an Intrusion Detection System (IDS) to secure routing in MANET. So on the beat this defect, we propose a cross-layer based IDS techniques. To use cross-layer techniques to detect and isolate malicious node in MANET then updating malicious node information within the routing table. For cross-layer, we use MAC and network layer. The medium access control (MAC) protocol allows mobile nodes to share a typical broadcast channel. The network-layer holds the multi-hop communication paths over the network. This paper gives the corresponding simulation results in NS2. With the help of performance metrics like packet delivery ratio, end-to-end delay, and throughput, it's shown that cross-layering between AODV and Modified DSR. This paper gives the result of AODV is best among the two protocols.