Hi Kalyan,
Basically, a certificate is signed by an Certification Authority (knwon as CA) this CA has a certificate that is known as "signer certificate". This CA has public certificate that is what you need to exchange between servers to be able to comunicate securely (TLS) between them , that is known as "exchange signers".
If the CA are known CA (versign, equifax, ...) normally you don't need to exchange certificates, with self-signed certificates you need to exchange because are yours.
Hope this helps. Tell us if you need more support
Regards