Test-vsg:
    Added test cases to check for path mtu across cord framework
    for end2end tests. Size of response from some sites may
    make response to get dropped.
    Validated with selected sites.

Change-Id: I92f0cbe424951d2476abd6a36cbfc8f910088670
diff --git a/src/test/vsg/vsgTest.py b/src/test/vsg/vsgTest.py
index 363dc74..e20383b 100644
--- a/src/test/vsg/vsgTest.py
+++ b/src/test/vsg/vsgTest.py
@@ -16,6 +16,7 @@
 import os
 import sys
 import json
+import requests
 from nose.tools import *
 from twisted.internet import defer
 from nose.twistedtools import reactor, deferred
@@ -515,6 +516,95 @@
         VSGAccess.restore_interface_config(mgmt, vcpe = vcpe)
         assert_equal(st, 0)
 
+    #Test cases to check path mtu across cord framework wih some selected websites to check response.
+    def test_vsg_to_retrieve_content_from_google_to_validate_path_mtu(self):
+        """
+        Algo:
+        1. Get dhcp IP to vcpe interface in cord-tester
+        2. Verifying vcpe interface gets dhcp IP
+        3. Retrieve contents from www.google.com and Verify response status is 200 ok.
+        4. This validates path mtu for end to end traffic with request to retrieve web contents in cord framework.
+           (Based on website response, size differs, needs check on MTU)
+        4. Restoring management interface configuration in  cord-tester
+        """
+        host = 'www.google.com'
+        vcpe = self.vcpe_dhcp
+        mgmt = 'eth0'
+        assert_not_equal(vcpe, None)
+        vcpe_ip = VSGAccess.vcpe_get_dhcp(vcpe, mgmt = mgmt)
+        assert_not_equal(vcpe_ip, None)
+        log.info('Got DHCP IP %s for %s' %(vcpe_ip, vcpe))
+        log.info('Initiating get requests to %s' %host)
+        r = requests.get('http://<%s>'%host)
+        VSGAccess.restore_interface_config(mgmt, vcpe = vcpe)
+        assert_equal(r.status_code, 200)
+
+    def test_vsg_to_retrieve_content_from_rediff_to_validate_path_mtu(self):
+        """
+        Algo:
+        1. Get dhcp IP to vcpe interface in cord-tester
+        2. Verifying vcpe interface gets dhcp IP
+        3. Retrieve contents from www.rediff.com and Verify response status is 200 ok.
+        4. This validates path mtu for end to end traffic with request to retrieve web contents in cord framework.
+           (Based on website response, size differs, needs check on MTU)
+        4. Restoring management interface configuration in  cord-tester
+        """
+        host = 'www.rediff.com'
+        vcpe = self.vcpe_dhcp
+        mgmt = 'eth0'
+        assert_not_equal(vcpe, None)
+        vcpe_ip = VSGAccess.vcpe_get_dhcp(vcpe, mgmt = mgmt)
+        assert_not_equal(vcpe_ip, None)
+        log.info('Got DHCP IP %s for %s' %(vcpe_ip, vcpe))
+        log.info('Initiating get requests to %s' %host)
+        r = requests.get('http://<%s>'%host)
+        VSGAccess.restore_interface_config(mgmt, vcpe = vcpe)
+        assert_equal(r.status_code, 200)
+
+    def test_vsg_to_retrieve_content_from_yahoo_to_validate_path_mtu(self):
+        """
+        Algo:
+        1. Get dhcp IP to vcpe interface in cord-tester
+        2. Verifying vcpe interface gets dhcp IP
+        3. Retrieve contents from www.yahoo.com and Verify response status is 200 ok.
+        4. This validates path mtu for end to end traffic with request to retrieve web contents in cord framework.
+           (Based on website response, size differs, needs check on MTU)
+        4. Restoring management interface configuration in  cord-tester
+        """
+        host = 'www.yahoo.com'
+        vcpe = self.vcpe_dhcp
+        mgmt = 'eth0'
+        assert_not_equal(vcpe, None)
+        vcpe_ip = VSGAccess.vcpe_get_dhcp(vcpe, mgmt = mgmt)
+        assert_not_equal(vcpe_ip, None)
+        log.info('Got DHCP IP %s for %s' %(vcpe_ip, vcpe))
+        log.info('Initiating get requests to %s' %host)
+        r = requests.get('http://<%s>'%host)
+        VSGAccess.restore_interface_config(mgmt, vcpe = vcpe)
+        assert_equal(r.status_code, 200)
+
+    def test_vsg_to_retrieve_content_from_facebook_to_validate_path_mtu(self):
+        """
+        Algo:
+        1. Get dhcp IP to vcpe interface in cord-tester
+        2. Verifying vcpe interface gets dhcp IP
+        3. Retrieve contents from www.facebook.com and Verify response status is 200 ok.
+        4. This validates path mtu for end to end traffic with request to retrieve web contents in cord framework.
+           (Based on website response, size differs, needs check on MTU)
+        4. Restoring management interface configuration in  cord-tester
+        """
+        host = 'www.facebook.com'
+        vcpe = self.vcpe_dhcp
+        mgmt = 'eth0'
+        assert_not_equal(vcpe, None)
+        vcpe_ip = VSGAccess.vcpe_get_dhcp(vcpe, mgmt = mgmt)
+        assert_not_equal(vcpe_ip, None)
+        log.info('Got DHCP IP %s for %s' %(vcpe_ip, vcpe))
+        log.info('Initiating get requests to %s' %host)
+        r = requests.get('http://<%s>'%host)
+        VSGAccess.restore_interface_config(mgmt, vcpe = vcpe)
+        assert_equal(r.status_code, 200)
+
     def test_vsg_for_external_connectivity_to_invalid_host(self):
         """
         Algo: