How to do session management in aspnet identity?

you may do this:

var fetchUser = context.UserMaster.Where(t => t.Email == model.Email).SingleOrDefault();
if (null == fetchUser)
    throw new Exception("Not found");
Session["User"] = fetchUser;

You can add as:

var listClaims=new[] { new Claims(ClaimsType.SerialNumber,Id), new Claims(ClaimsType.Name,FullName), new Claims(ClaimsType.HomePhone,ContactNumber), new Claims(ClaimsType.Gender,Gender)};

var oAuthIdentity=new ClaimsIdentity(listClaims, otherparameter ...);

For more details you can check System.Secutity.Claims.ClaimTypes

Since you are using Asp.Net Identity, you want to store session related stuff as claims. This is very easy to extend with customised claims.

As an aside, I think you'd be better off simple extending ApplicationUser to hold the additional data, as detailed here.

That said, here is a complete example of how to add custom claim types to your application.

Step 1 - Define one or more custom claim types to hold your additional information

public static class CustomClaimTypes
{
    public const string MasterFullName = "http://schemas.xmlsoap.org/ws/2014/03/mystuff/claims/masterfullname";
    public const string MasterUserId = "http://schemas.xmlsoap.org/ws/2014/03/mystuff/claims/masteruserid";
}

A claim type is just a unique string that identifies the specific claim. Here we are just using a similar format as the built in claim types.

Step 2 - During the sign in process, set values for the custom claim types

private async Task SignInAsync(ApplicationUser user, bool isPersistent)
{
    AuthenticationManager.SignOut(DefaultAuthenticationTypes.ExternalCookie);
    var identity = await UserManager.CreateIdentityAsync(user, DefaultAuthenticationTypes.ApplicationCookie);

    //Fetch data from the UserMaster table 
    var userdata = GetdatafromUserMaster();

    //Using the UserMaster data, set our custom claim types
    identity.AddClaim(new Claim(CustomClaimTypes.MasterUserId, userdata.UserId));
    identity.AddClaim(new Claim(CustomClaimTypes.MasterFullName, userdata.FullName));

    AuthenticationManager.SignIn(new AuthenticationProperties() { IsPersistent = isPersistent }, identity);
}

Note: we are using custom claim types so that we preserve the existing NameIdentifier and Name claims, and can therefore easily access identity information from both Asp.Net Identity and our custom UserMaster table.

Step 3 - Add extension method(s) to IIdentity so we can easily access our custom claim data

public static class IdentityExtensions
{
    public static string GetMasterUserId(this IIdentity identity)
    {
        if (identity == null)
            return null;

        return (identity as ClaimsIdentity).FirstOrNull(CustomClaimTypes.MasterUserId);
    }

    public static string GetMasterFullName(this IIdentity identity)
    {
        if (identity == null)
            return null;

        return (identity as ClaimsIdentity).FirstOrNull(CustomClaimTypes.MasterFullName);
    }

    internal static string FirstOrNull(this ClaimsIdentity identity, string claimType)
    {
        var val = identity.FindFirst(claimType);

        return val == null ? null : val.Value;
    }
}

Nothing fancy here. We just cast the IIdentity as a ClaimsIdentity and then return the value of either the first claim of the given CustomClaimType that we find, or we return null if a claim doesn't exist.

Step 4 - Now we can access our custom claim data in views and/or controllers really easily. Say you wanted to use the full name from your UserMaster table instead of the ApplicationUser? You can now do this:

<ul class="nav navbar-nav navbar-right">
    <li>
        @Html.ActionLink("Hello " + User.Identity.GetMasterFullName() + "!", "Index", "Manage", routeValues: null, htmlAttributes: new { title = "Manage" })
    </li>
    <li><a href="javascript:document.getElementById('logoutForm').submit()">Log off</a></li>
</ul>

You can also do the same thing from within a Controller.