diff --git a/scapy/contrib/igmp.py b/scapy/contrib/igmp.py
index 3e0698037..5abd91188 100644
--- a/scapy/contrib/igmp.py
+++ b/scapy/contrib/igmp.py
@@ -23,6 +23,7 @@ from scapy.fields import *
 from scapy.layers.inet import *
 from scapy.layers.l2 import DestMACField, getmacbyip
 from scapy.error import warning
+from scapy.compat import chb, orb
 
 def isValidMCAddr(ip):
     """convert dotted quad string to long and check the first octet"""
@@ -73,15 +74,15 @@ IGMPv2 message format   http://www.faqs.org/rfcs/rfc2236.html
         p += pay
         if self.chksum is None:
             ck = checksum(p)
-            p = p[:2]+chr(ck>>8)+chr(ck&0xff)+p[4:]
+            p = p[:2]+chb(ck>>8)+chb(ck&0xff)+p[4:]
         return p
 
     @classmethod
     def dispatch_hook(cls, _pkt=None, *args, **kargs):
         if _pkt and len(_pkt) >= 4:
-            if ord(_pkt[0]) in [0x22, 0x30, 0x31, 0x32]:
+            if orb(_pkt[0]) in [0x22, 0x30, 0x31, 0x32]:
                 return IGMPv3
-            if ord(_pkt[0]) == 0x11 and len(_pkt) >= 12:
+            if orb(_pkt[0]) == 0x11 and len(_pkt) >= 12:
                 return IGMPv3
         return IGMP
 
diff --git a/scapy/contrib/igmp.uts b/scapy/contrib/igmp.uts
index 951ca802b..ee6282899 100644
--- a/scapy/contrib/igmp.uts
+++ b/scapy/contrib/igmp.uts
@@ -45,7 +45,7 @@ assert x[IP].dst == "224.0.0.1"
 x = Ether(src="00:01:02:03:04:05")/IP()/IGMP(gaddr="224.2.3.4", type=0x12)
 x.mrcode = 1
 x[IGMP].igmpize()
-x = Ether(str(x))
+x = Ether(raw(x))
 assert x.mrcode == 0
 
 x.gaddr = "224.3.2.4"
@@ -64,7 +64,7 @@ assert IGMP().mysummary() == "IGMP Group Membership Query 0.0.0.0"
 ~ netaccess
 
 x = Ether(src="00:01:02:03:04:05")/IP(dst="192.168.0.1")/IGMP(gaddr="www.google.fr", type=0x11)
-x = Ether(str(x))
+x = Ether(raw(x))
 assert not x[IGMP].igmpize()
 assert x[IP].dst == "192.168.0.1"
 
diff --git a/scapy/contrib/igmpv3.uts b/scapy/contrib/igmpv3.uts
index ef52eb369..89034a335 100644
--- a/scapy/contrib/igmpv3.uts
+++ b/scapy/contrib/igmpv3.uts
@@ -13,7 +13,7 @@ x = a/b/c
 x[IGMPv3].igmpize()
 assert x.mrcode == 20
 assert x[IP].dst == "224.0.0.1"
-assert isinstance(IGMP(str(x[IGMPv3])), IGMPv3)
+assert isinstance(IGMP(raw(x[IGMPv3])), IGMPv3)
 
 = Dissect IGMPv3 - IGMPv3mq
 
@@ -22,7 +22,7 @@ assert IGMPv3 in x
 assert IGMPv3mq in x
 assert x[IGMPv3mq].gaddr == "224.0.0.2"
 assert x.summary() == "Ether / IP / IGMPv3: 192.168.0.1 > 127.0.0.1 Membership Query / IGMPv3mq"
-assert isinstance(IGMP(str(x[IGMPv3])), IGMPv3)
+assert isinstance(IGMP(raw(x[IGMPv3])), IGMPv3)
 
 = Dissect IGMPv3 - IGMPv3mr
 
@@ -32,7 +32,7 @@ assert IGMPv3mr in x
 assert len(x[IGMPv3mr].records) == 2
 assert x[IGMPv3mr].records[0].srcaddrs == ["192.168.0.1", "192.168.132.247"]
 assert x[IGMPv3mr].records[1].maddr == "4.4.4.4"
-assert isinstance(IGMP(str(x[IGMPv3])), IGMPv3)
+assert isinstance(IGMP(raw(x[IGMPv3])), IGMPv3)
 
 = Dissect IGMPv3 - IGMPv3mra
 
@@ -41,6 +41,6 @@ assert IGMPv3 in x
 assert IGMPv3mra in x
 assert x[IGMPv3mra].qryIntvl == 3
 assert x[IGMPv3mra].robust == 2
-assert isinstance(IGMP(str(x[IGMPv3])), IGMPv3)
+assert isinstance(IGMP(raw(x[IGMPv3])), IGMPv3)
 
 = IGMP vs IVMPv3 tests