What is the Mac Mohan line?

When the border dispute between India and Pakistan took a radical turn, then a bilateral agreement was reached between late Prime Minister Lal Bahadur Shastri and then President General of Pakistan General Ayub, the mediator of this mediated Soviet Union said that according to India border Mc Mohan Line was considered as prescribed by the British government since the British rule. Both the national line would always be careful that such a format was signed